If you think 20,000 visits in 24 hours is a lot, it's not. It just isn't. It hasn't been since 1998.
But the audience is valuable.
Compare this to something like the frontpage of Reddit for a guest and you'll see a lot higher than that... but from a very broad audience.
Compare this again to something like Facebook, if your site has been shared across (and not just some humorous image that has been reuploaded and shared).
Imagine if you used that post to say "Here is why this webhost sucks, rah rah rah", and then funneled them into another company. Imagine if you hired sock puppet accounts to upvote your comments both here and on other social sites, if you are either an affiliate or a web hosting company you have the potential to make a lot of money off the right traffic source.