High number of direct requests

[sodani]

I'm getting about 500 visits to my site per day, and about 600 hits. Of the 600 hits, I'd say that about 550 have no referer, that is, they're showing up as a direct request. My domain name isn't a dictionary word, and I'm having a hard time believing that so many of these visitors are just typing in the URL. What can I do to further learn how people are ending up on my site? I'm using webalizer.

[sodani]

I tried adding some adsense onto this site but the impressions that adsense was reporting was really low, which leads me to believe that all these visitors I'm getting are bots.