Iveta's links to Web 2.0 sites

Hey, I would also like to contribute to this web 2.0 sites overview :)
As most of us, I use facebook , then igoogle and youtube. Similar kind of stuff as youtube can be done at Metacafe or czech Stream.cz , where users can add their videos or watch some pieces from czech tv channel, but I don't use it much.
I use Wikipedia, but only as a passive user, I do not contribute to the content. Then I sometimes go to Lyricwiki which is good when I need to find lyrics of songs I like.
I started my blog lately, but it is really a beta version, I still haven't found out everything I need from the CMS I'm using there..
I go almost every day to discussion forum nyx.cz where you can find a topic you are interested in and join easily with people with same interests. There are both chatting boards and more professional ones, which can be helpful if you have troubles when solving a problem. You can also present your pictures there and discuss about them and each user has a blogging space.
We used Slideshare quite a lot during one of my classes, our teacher always placed his presentations there. It's a good place when you want to show your presentations to group of people or find people who are into the same topic as you.
For listening to music, I sometimes go to last.fm but I think it has changed lately and I don't like it as much as before. I used to go more to Radioblogclub.com.