Delicious and more recently Diigo to sort out and share useful links I come across. I restrict my following here to a select few posting on educational technology and I glimpse in once a month or so.
I stay on top of RSS feeds from a very wide range of sources with Bloglines I still haven't crossed over to Google Reader but I think this has huge potential. I review feeds from this for 20 minutes each day.
I use Flickr mostly for personal stuff and the occasional conference shot when I get the urge but I am more likely to be talking to folk than skipping around with a camera . I use Youtube on this basis too but in the main I crowdsource materials through these mediums Increasingly I use Slideshare and Scribd as sources for bits of information to start me thinking - I'll follow up with links to some good presentations from Slideshare.
In last year I have also been using Friendfeed to follow folk around me in Scottish Education. I have been impressed by @mikecoulter and colleagues in Learning and Teaching Scotland who are making really great progress in moving into this new learning and development space. They are mostly to be found in my Bloglines Roll at the side of this posting.