Collaboration Tools

Honestly, I am really not sure which collaboration tool I would use the most.  I think I like the edmodo best.  I like how I can limit who is involved with the conversation.  I think it would be an easy way to do a book discussion.  Then again.... I love the Cover it Live.  Students could almost have the same experience as a socratic seminar.  Here they would be typing responses to one another instead of talking.  Middle schoolers HATE waiting their turns.  With Cover it Live they could respond immediately.