I choose Google docs and Todaysmeet. My todaysmeet address is http://todaysmeet.com/MDE
and it is up and running for one week.
This is a cool tool that I can see using for several of my discussion topics in Health Fitness. One discussion that gets lots of questions is smoking. After my lesson I can have students go to this site and type in their questions. I can pick the most important questions and then discuss the next day. This could be done in the classroom in small groups to encourage participation.
The other product I've explored was Google Docs, which I have used before, primarily with schedules between the specialists. Natali has sent several docs my way to see if the subject matter is appropriate and useful for our muscle unit.