All classrooms will benefit from having dedicated access accounts to a wide variety of social media. Not only does this create the ability to collaborate, but it connects your classroom, and your students' accomplishments, to parents and community.
Create a Classroom Google Account
creating
Gmail Email
Calendar sharable calendar service with auto alerting
Blogger blogging platform which works on all platforms including mobile
Odiogo (a non-Google service) allows your blog to talk for free
Google Books sharable library access to billions of books
YouTube Video Sharing
Documents equivalents to Word, Excel, PowerPoint, all open and usable by multiple users in real time
Mike Thornton's Third Grade Simple Machines Google Doc
Google Sites simplified Wiki (this is one)
Picasa photo sharing
Google+ Hangout Access Live Video Connection
Skype free live global video calling
Classroom Twitter Account
crowdsource questions, explain what you are doing, offer links and news (see also Twitpic)
Spacefish and the Primary Crowdsource
ds106 Radio Digital Storytelling
Online Social Radio
UStream Live Internet Television from anywhere and almost any linked device
Evernote Social Bookmarking
Diigo Social Bookmarking
Flickr Photo Sharing
Vimeo Video Sharing
No sign up needed to use TodaysMeet, just open it up, name your "room," and pass that web address (http://todaysmeet.com/yourroomname) out to those you want to participate.