Web 2.0

So I know we were supposed to write a topic on Web 2.0 and I know its kinda late but honestly it was because I didn't really feel I had a lot to add this year.  I mean I think Web 2.0 is great - there are a ton of really useful sites out there than Mike has shown us (Shelfari, Wikipedia etc etc etc etc etc etc etc)  and I am sure I am going to use a lot of them in class.  Recently one of our other profs told us that a recent study found that Wikipedia is actually 'correct' more often than printed versions of the Encyclopedia Britannica - so obviosly Web 2.0 sites and resources are effective and they ARE going to be part of the classroom in a VERY big way.  But honestly saying that really hasn't changed my outlook much over the past year.  Bascially, there are a million options out there; as teachers we have to find creative ways of using them for a miriad of reasons; and the net has become so inundated with Web 2.0 stuff that really its almost impossible NOT to use it if you are using the internet.
I do find the idea of Web 3.0 interesting - and honestly a little scary.  I'm not sure why really, but the idea of google or other internet companies collecting enough information on all of us to predict our needs is just a little - well - scary.  I am sure I will use it when it comes along to a greater extent, but it still gives me a little nervous itch at the back of my head.  Any comments?