Surely it's all relative? Sure, 20,000 people in a day might not be a lot when compared to 'total people using the internet every day' or even 'total people looking at HN every day' but it's a huge number when compared to 'total people looking at my blog on an average day'.

20,000 isn't that high, but it's specific traffic - people coming from one source who are generally in the same niche group.

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.

That's similar figures to what I got when one of my sites got to the top. It would be interesting to see the fall off rate of # of visitors based on its rank on the front page.