Backchannel discussion using a Google Docs class agenda

In trying to increase class participation and interaction this week during a computer lab activity I'm trying to utilize the built-in discussion feature in Google Docs. I've created an agenda for the day that includes links to the Geometer Sketchpad activity file to be downloaded, the activity sheet that is to be completed and the directions for the day. I have created the discussion threads to be centered on each individual question along with a lesson feedback thread students can comment on if they wish.

It would be great if someday I could include my math or technology personal learning network (PLN) from Twitter to give the students a view of the educational value of Twitter in an open classroom environment but am hesitant in opening it up to that level at this time.
--Any comments or suggestions on that issue? Has anyone tried that with students before?

Here are the discussion board guidelines I am asking the students to consider prior to any post:

1. To let others know who you are responding to, use the @ symbol before their name. For example, since I am responding to myself I would type @andrew_schwen at the beginning of my message.
2. Posts need to be directly related to the activity and should be professional/academic in their content.
3. Reply to the discussion threads below by clicking "reply" rather than starting a new thread for your posts.

I'd love to hear your thoughts or experiences on this practice in the classroom as this is relatively new territory for me.