Which websites offer a wide range of sub-communities for different subjects?

If you mean websites that contain lots of separate communities organized around different interests, these are some of the best:

• Reddit — Probably the clearest example. It has thousands of topic-specific subreddits, covering everything from science and programming to hobbies, sports, books, and local communities.
• Stack Exchange — A large network of separate Q&A communities, each focused on a particular subject, such as mathematics, programming, photography, cooking, and more.
• Lemmy — A decentralized, Reddit-like network where individual communities focus on particular subjects.
• Discord — Thousands of independent servers organized around games, programming, music, education, hobbies, fandoms, and other interests. Unlike Reddit, it's primarily real-time chat.
• Quora — Broad subject-based Q&A, although its communities are less distinctly separated than Reddit's.
• GitHub Discussions — Particularly useful for communities centered around specific open-source projects and technologies.

If you're trying to find communities

There are also directories that search across multiple platforms:

• Hive Index — Currently catalogs thousands of communities across dozens of platforms and lets you browse by topic.
• Forum Finder — Searches communities across Reddit, Discord, Facebook, Slack, Telegram, forums, and other platforms.
• FindAReddit — Specifically helps you discover subreddits by niche, with thousands of categorized communities.

If you're looking for the closest thing to a giant "mall of communities," I'd start with Reddit. If you want more specialized, knowledge-focused communities, Stack Exchange is better. If you want to discover communities across many different websites, Hive Index is particularly useful.

Here are some of the top websites that offer a wide range of dedicated sub-communities for different subjects, hobbies, and interests:

• Reddit - Known as the "front page of the internet," it features hundreds of thousands of active, niche communities called subreddits (e.g., r/science, r/cooking) covering virtually every topic imaginable. You can browse and join discussions on Reddit.
• Discord - While structured around chat servers rather than a traditional forum, it hosts millions of public and private communities dedicated to specific games, study groups, art styles, and tech stacks. You can explore public servers via Discord Discover.
• Stack Exchange - A massive network of question-and-answer communities focused on specific technical, professional, and academic subjects, ranging from programming (Stack Overflow) to mathematics, history, and literature. You can explore the network on Stack Exchange.
• Quora - A knowledge-sharing platform where users follow and contribute to specific "Spaces" dedicated to distinct topics, personal interests, industries, and academic fields. You can check it out at Quora.
• Substack - A platform where writers, experts, and creators build independent publishing communities with dedicated comment sections, subscriber chats, and niche subject matter focus. You can discover creators and publications on Substack.
• Goodreads - A specialized social networking site for readers that breaks down into thousands of specific book clubs, genre groups, and reading challenges. You can find these on Goodreads.

Would you like to narrow these down based on a specific subject you are looking to explore, or are you looking for a particular format (like live chat vs. long-form forums)?

If you mean websites that themselves contain lots of separate communities organized by subject, these are some of the best options:

• Reddit — Probably the broadest and easiest choice. It has thousands of topic-specific subreddits, covering hobbies, science, technology, entertainment, careers, sports, local communities, and very niche interests.
• Stack Exchange — A network of specialized Q&A communities. Particularly strong for programming, science, mathematics, language, history, and other knowledge-oriented subjects.
• Lemmy — A decentralized Reddit-like network consisting of many independently run communities covering different topics.
• Discord — Has enormous numbers of individual servers organized around games, hobbies, creators, software, fandoms, and other interests. It's more chat-oriented than Reddit.
• The Hive Index — Especially useful if you want to discover communities across multiple platforms. It catalogs thousands of communities across Reddit, Discord, Slack, Facebook, LinkedIn, independent forums, and many others, organized by topic.
• OpenCommunity — Another community directory spanning Discord, Slack, Telegram, Reddit, WhatsApp, and other platforms, with categories such as technology, design, business, gaming, learning, and careers.

If you're looking for the closest thing to "a giant website with a community for almost anything," I'd start with Reddit. If your goal is specifically to discover communities scattered across the internet, The Hive Index is more useful.

• Reddit : A massive platform organized into hundreds of thousands of active communities called subreddits. It covers nearly every topic imaginable, from niche hobbies and professional fields to local regions and entertainment. You can explore the directory on Reddit.
• Discord : A communication platform built around invite-only and public servers dedicated to specific subjects, ranging from gaming and art to studying and tech development. You can find public communities through the Discord Server Directory.
• Quora : A question-and-answer platform where users group discussions, articles, and queries into "Spaces" centered around specific subjects, interests, or expert domains. You can browse topics on Quora.
• Stack Exchange : A network of specialized, highly-focused question-and-answer communities covering distinct subjects like programming, mathematics, cooking, and photography. You can explore the network on Stack Exchange.
• Substack : A publishing platform where independent writers host newsletters that double as vibrant reader communities, complete with comment threads and niche discussion forums for specific political, cultural, or creative subjects. You can discover publications on Substack.
• Disboard : A comprehensive public server listing service specifically designed to help users search and discover active Discord communities across hundreds of distinct categories and subjects. You can search listings on Disboard.

If you have a specific subject or hobby in mind, I can recommend which of these platforms has the most active or highest-quality sub-community for it.

If you mean websites where you can find lots of separate communities organized around different interests, these are some of the best:

1. Reddit — Probably the closest match. It has thousands of topic-specific subreddits/communities, covering everything from technology and science to hobbies, games, careers, and local interests.

2. Stack Exchange — A network of specialized Q&A communities. It's particularly strong for programming, science, mathematics, technology, languages, academics, and other knowledge-focused subjects.

3. Discord — Has enormous numbers of independently run servers devoted to particular games, hobbies, fandoms, professions, creators, and interests. Servers can also contain multiple topic-specific channels.

4. Tumblr — Its Communities feature provides topic-oriented groups for interests such as photography, gaming, biology, and various fandoms.

5. Facebook Groups — Very broad range of groups, including hobbies, local communities, professional interests, buying/selling, clubs, and support-oriented communities.

If you're looking for the Reddit-like experience

I'd rank them:

Reddit → Discord → Stack Exchange → Facebook Groups → Tumblr

Reddit is the standout if your goal is to browse a huge directory of communities and jump between completely different subjects. Its communities can also be public, restricted, or private.

If you tell me the types of subjects you're interested in (e.g. books, AI, history, fitness, investing, obscure hobbies), I can also give you the best community websites specifically for those subjects.

• Reddit : Known as the "front page of the internet," it hosts hundreds of thousands of active communities (subreddits) dedicated to every imaginable topic, from niche hobbies and academic disciplines to local news and pop culture. You can explore them directly on Reddit.
• Discord : Features countless public servers organized around specific interests, gaming franchises, study groups, and creative arts, offering real-time chat sub-communities. You can find and join communities through the Discord Discover Page.
• Quora : A question-and-answer platform where users run and follow "Spaces"—dedicated sub-communities focused on specific subjects, ideologies, or shared curiosities. You can browse these groups on Quora Spaces.
• Stack Exchange : A network of distinct, highly focused Q&A communities covering topics from programming (Stack Overflow) to mathematics, DIY, and literature. You can see the full directory on the Stack Exchange Sites List.
• Goodreads : A community-driven platform for book lovers that breaks down into thousands of sub-groups based on specific genres, reading challenges, authors, and book clubs. Explore the groups directory on Goodreads Groups.

If you are looking for sub-communities in a specific category (like gaming, academics, or professional networking), let me know and I can recommend the best platform for that exact interest.

Several major platforms and websites are specifically structured around offering a diverse, sprawling network of sub-communities covering virtually every subject imaginable:

• Reddit is the quintessential example of a macro-site built entirely out of micro-communities. Known as subreddits, these distinct spaces cover everything from global news, science, and literature to hyper-niche hobbies, local regions, and fandoms.
• Discord functions as a massive directory of real-time chat servers. While it started in gaming, public servers now exist for nearly every subject, including coding, bird watching, music production, and academic study.
• Stack Exchange is a network of question-and-answer sub-communities focusing heavily on technical, scientific, and specialized subjects. It spans independent communities like Stack Overflow for programming, Super User for computer hardware, and dozens of others for mathematics, history, and philosophy.
• Quora operates as a knowledge-sharing community organized by topics and spaces. Users can follow or contribute to specific subject-driven micro-communities ranging from artificial intelligence and psychology to pop culture and DIY crafts.
• Tumblr relies heavily on user-curated tags, blogs, and interest-based groups that function as tight-knit sub-communities centered around art, writing, fandoms, and niche aesthetics.

If you are looking for sub-communities for a specific subject (like tech, gaming, or learning a skill), let me know and I can recommend the best platform for that niche.

If you're looking for websites that organize discussions into many topic-specific communities (similar to Reddit's subreddits), here are some of the best options:

• Reddit — The largest example, with hundreds of thousands of communities covering nearly every topic imaginable, from hobbies and careers to science, gaming, and local regions.
• Quora — Organized around questions and answers, with topic pages and "Spaces" dedicated to specific interests.
• Stack Exchange — A network of specialized Q&A communities for programming, mathematics, science, photography, language learning, and dozens of other subjects.
• Discord — Contains millions of servers dedicated to gaming, education, art, music, technology, and countless niche interests. Each server functions as its own community.
• Facebook Groups — Offers communities for local events, hobbies, professions, support groups, and almost any interest.
• Lemmy — A decentralized Reddit-style platform with topic-based communities spread across interconnected servers (the Fediverse).
• Mbin — Another Fediverse platform featuring communities, discussions, and link sharing that interoperates with Lemmy.
• Amino — Focused on fandoms and hobbies, with individual communities ("Aminos") for anime, books, games, sports, music, and more.
• GitHub Discussions — Many open-source projects host their own discussion communities for questions, ideas, and support.
• Discourse Hub — Thousands of independent forums powered by Discourse software, covering technology, education, nonprofits, gaming, and more.

Depending on what you're after, one platform may fit better than another:

• For general discussions on almost any subject: Reddit or Lemmy.
• For expert answers: Stack Exchange or Quora.
• For real-time conversations: Discord.
• For hobby and fandom communities: Amino.
• For project- or product-specific communities: GitHub Discussions or Discourse forums.

If you're trying to find communities about a particular topic across multiple platforms, tools like urlForum Finderturn0search1 can search Reddit, Discord, Facebook Groups, Slack, Telegram, and other community platforms at once.

Several major platforms and websites are specifically structured around hosting vast networks of sub-communities covering virtually every niche, hobby, and academic subject imaginable:

• Reddit is the quintessential example, divided into millions of individual user-run sub-communities called subreddits (prefixed with r/ ) covering everything from global news and science to hyper-specific hobbies. You can explore them directly on the Reddit Home Page.
• Discord functions as a massive directory of real-time chat servers dedicated to specific fandoms, study groups, gaming communities, and technical subjects, searchable through various community boards. You can look for active spaces via the Discord Discovery Page.
• Facebook Groups hosts immense, active micro-communities centered around local neighborhoods, cooking, parenting, school grade levels, and specific collecting niches. You can access these via Facebook.
• Skool is an all-in-one platform heavily populated by creator-led, subject-specific communities focusing on professional skills, software development, and gamified learning. You can browse creator networks at Skool.
• Mighty Networks allows brands, educators, and independent creators to host deeply integrated, topic-specific sub-communities paired with courses and events. You can see how they operate on Mighty Networks.

If you're looking for a community for a specific subject or hobby (like coding, gaming, or finance), let me know and I can recommend the best platform and specific group for it.

If you're looking for websites organized into many topic-specific communities (similar to Reddit's subreddits), there are several good options depending on what kinds of discussions you want:

• Reddit – The largest example, with hundreds of thousands of user-created communities covering nearly every subject imaginable.
• Lemmy – A decentralized Reddit-like platform where independent servers host communities that can interact with one another. It's especially popular among open-source and privacy-focused users.
• Mbin – Another decentralized community platform compatible with the Fediverse, offering magazine-style communities similar to subreddits.
• Quora – Best known for questions and answers, but also includes topic pages and community-created Spaces for ongoing discussions.
• Discord – Organized around servers rather than forums. Thousands of public servers exist for gaming, programming, hobbies, education, entertainment, and more.
• Facebook Groups – Hosts millions of groups centered on local communities, hobbies, professions, and special interests.
• Amino – Designed around fandoms and interests such as anime, gaming, K-pop, books, movies, and TV shows.
• Hacker News – Focused on technology, startups, programming, and science rather than general-interest topics.
• Slashdot – Long-running technology news and discussion community with topic-based comment threads.
• Stack Exchange – A network of over 170 Q&A communities covering programming, mathematics, science, photography, cooking, language learning, and many other subjects.

If you're mainly interested in discovering communities across many platforms rather than staying on one website, urlForum Finderturn0search1 searches Reddit, Discord, Facebook Groups, Slack, Telegram, GitHub Discussions, and other community platforms at once.

For broad, Reddit-style discussion across many unrelated topics, Reddit, Lemmy, and Mbin are the closest matches. If you're interested in a specific area—such as technology, gaming, academics, or fandoms—you'll often find more focused and knowledgeable communities on platforms dedicated to those interests.