Wallwisher - very cool and something that could easily be used as an exit ticket for a daily question or a post as a student travels between stations. Students could even be allowed to create walls of their own for classmates to post on as part of an assignment
Voice Thread - this seems like a fun way for kids to get involved with a classroom project. I played with this a little, but am not one to like my own voice to be recorded. I don't think out students have that same problem ;o) I found a thread created by a teacher regarding safety - this can be used to model for the students what a product might look like to give them ideas and guidance.
Grouply - I learned about this site this summer when teaching summer school. The high school teachers at Spring Woods use this and the kids were very engaged, very involved and had no problem catching on to how to manage the site. Once members are invited to participate, they have the opportunity to chat, record messages, post remarks and more. I have just started to work with this, so the product below is far from impressive. I am anxious to see how it develops during the new year and if it is something that will work well with our blog.
Any of these tools as well as the others are great for students that might otherwise be hesitant to speak out in class. Posting a remark with the comfort of time to revise and review comments may be more appealing to some students - in addition, they LOVE to text and post on Facebook. This may be a way to get them interested by allowing activities they already love to do.