I find the front page basically without value... ...but individual subreddits for can be quite valuable global public spaces for specific topics. They're centralized, searchable, and generally don't put any walls in front of non-registered users. A lot of internet searches will lead you to years-old posts on a subreddit dedicated to the subject, with a long discussion thread, and links to more of that same content on that same subject. Forums previously filled this function (and usenet before), but Reddit has the advantage of a more modern and consistent interface. Facebook groups could have potentially filled this role, but are totally opaque to outside searches, and so are not easily discovered.