Does it? Search for $topic on Reddit and you are guaranteed to find forum posts related to $topic, and very possibly at least one forum (subreddit) dedicated thereto. On the broader web, there's no guarantee of finding anything at all. Plus you can look at other people's subscriptions and posts to see what they follow. And sometimes you can just take a wild guess and go to /r/$topic and it will be what you're looking for. It's definitely better than zero.