I have several new sites monetized with adsense/amazon/affiliates that are subdirectories of http://www.useful-info-for-you.com They are all linked from the main page(ignore my amateurish main page for now). Can you guys look at them and determine whether I should change each site to a subdomain? The subjects vary so much, that I'm afraid the search engines won't figure out what the sites are about, and I'll end up at the bottom of the search engine rankings. Thanks for any advice you can give me.
Wikipedia covers a gazillion of different topics and they seem to be doing quite well. So I wouldn't worry about that and put it all in sub-folders.