This was quite a survey of Web 2.0 tools - and I have recommended this course many times. When all is said and done, however, I think each of us takes what we can, and no one uses everything they learn!
First of all, I blog frequently - required at work, occasionally commenting on the blogs of others - I feel it is one of the easiest and best ways to get information onto the Web, and keep your readers informed.
Secondly, I use wikis and have told several staff members about wikis, as a quick and easy collaborative Web site.
The whole concept of collaboration, which comes along with these tools, is one which I push - to teachers, students, anyone who will listen. This is a new era of user-created content, and is an exciting way for everyone to make certain his/her voice is heard.
I use the RSS feeds on Google Reader and my del.icio.us accounts all the time. I can save, sort, read, refer, research so much more quickly and easily than in the past. Again, I recommend these time savers to anyone who is interested.
Best of all, I was able to do a successful collaborative presentation with another librarian for our monthly district meeting, about many of these tools. We met F2F only once, then used Google Docs to develop an outline, finally e-mailing the finished product. She's done a great deal more with mash-ups than I, so the presentation was really a great deal of fun.