The more I look into this the more I realise how much stuff is Web 2.0 and also how much of that stuff has been around since the early nineties. Web 2.0 is a bit of a rubbish word for all this web technology really! Anyway a nice list of Web 2.0 applications.
Amongst those I found loads of stuff I'm already well acquainted with. Wikipedia being the main one. Pretty much everyone who's ever surfed the net must have surely visited Wikipedia at some point. If you haven't edited anything, then try it now, find an article (your home town is always a good place to start) and correct it, there's bound to be typos or inaccuracies. Two areas that inevitably lead to criticism of Wikipedia.
OK, a lot of the criticisms are valid, particularly accuracy and lack of depth but if you look at the quantity of featured articles and their quality, these articles surely must be atleast an alternative to the Encyclopedia Britannica if not a replacement. However its still nice to have around even if it is just use for answering pub quiz questions.
I now get annoyed that I can't press edit when reading a book to correct grammar! Although that's probably also an after effect of reading "Eats, shoots and leaves".