What have you noticed about the various platforms that you have opened accounts on? What do they have in common? How do they differ?
That question is too big for this time of night!

Are these environments different from LMS (like Blackboard, WebCT, Moodle and others)? How?
Yes these tools are very different to most LMSs. Moodle does go in this direction but I hear that the others are less open to communication and collaboration.

What does “social media” mean for you? Which social media have you used already and what are your feelings about it?
I use delicious a lot, but mostly for myself, I enjoy flickr but rarely post my own stuff., I rarely blog. Some of this stuff will certainly be useful to me, the mashup with Google Earth for instance. Some things are hard to predict. I can’t imagine becoming a twitterter but I bet kids like it. A lot of these things draw you in while you’re there (e.g. the 43 trio) but I have no inner need to return, I feel rather that I’ve wasted my time a bit.

I enjoy helping to create something useful and meaningful, like Wikipedia pages. On the other hand, now that Wikipedia has started taking itself too seriously, the fun is draining out of it. This might be a danger for other applications., too