I created an account with Edmodo. I know CBE will use this along with the Daily 5 discussion . I like that you can create multiple groups so communication is possible with a variety of people. You can have groups set up for faculty as well as a groups set up for students and subject areas if you choose to do that.
I also checked out wallwisher. This can be used as an introductory tool for students to tell about themselves and make connections with their peers. I could see using this for vocabulary that will be used in upcoming units of study.
As for skype, we could use this to connect with the other first grade classrooms. Students from other rooms could work together on projects and share information with one another.