Easy to use blog, integrates with your browser a treat and I don't have to host it myself. I particularly like it for making reflective notes on articles I've read online and doing a brain dump before getting on with 'real' work.
Part of conglomo-google... but otherwise pukka!
An excellent free mind mapping site. You can work on your own or collaboratively, share your mind maps, export them as graphics and rich text (or other formats if you fork out). Not too fancy, not too limited. A Ronseal bit o' web 2.0
Bookmark, share, tag, comment, network... great for pooling resources or even just tracking down links which have tags you're interested in.
If you're sent a file in a format you can't open... then Zamzar can bash a way in for you by converting it to something you have got. You can even convert things like pdf files into stuff you can edit. V.handy!
5. Google Notebook
Yes, another Google offering - and I also use Google Reader too... I'm addicted to Google... so shoot me
Again, I love the browser integration, I like having my notes on any computer I happen to be using. I like the way you can edit your notes using Google Docs (feed that Google-addiction woman!) and it's fantastic for keeping track of quotes and references when you're off doing online research
I have to admit... I don't use this... yet. But, I do really like the look of it and the prospect of being able to embed presentations in a web page could be really handy when the OU VLE comes on-stream properly
I'm sure there are others too, so I'll revisit this 'un at a later date!
Stuff I don't get...
SecondLife - nope. Don't get it. Nope.
YouTube - okay, so there's some good stuff on there but just soooooooooooooooooooooooo much dross, but I can't see me wanting to upload anything I've created in a hurry)
MySpace - tried it... didn't get it... got out.
Elgg - 'elearning platform'... train has left the station
Flickr - tried it... ermmm... useful in a 'look at my photo albums' kinda way... but... ermmm