Web 2.0 Sites

I was looking at award winners for web 2.0 site. I didn't realize how many different kinds of sites there are that are considered "2.0." Sites such as craigslist, which I believe my roommate is addicted to for some reason, and even google maps fall under web 2.0. I use some of the listed sites regularly, especially google maps, and now twitter and facebook for this class. Some of these sites are even just newsfeeds and picture sharing sites, which is pretty cool. Even though I feel I don't use many of these listed sites, I find myself using some of them quite often.