I LISTEN TO Monday night chats on Twitter and learn a lot of things. There's a List.ly compilation that answers the recurring question, "What sites do you use in your classrooms?"
I have a personal shortlist, one that mirrors the time-motion movements I make during most days. In my case, I have a GTD logic behind selecting Evernote, Dropbox, Audioboo, Pinboard, Twitter, Flickr, LinkedIn, Google Plus, SproutSocial, Facebook and basic email-to-blog as my preferred watering holes for the work I do at third level in Ireland. Dale Borgeson has made an excellent List.ly List below that hundreds of teachers have reviewed and curated. Their sharing gives helpful clues about simple web services that can help in many classroom settings.