Google Plus (Google+) is a great resource for educators. You can connect with other educators and share, learn and collaborate, you can keep up with news and current events, you can connect with friends, and you can have video conferences called Hangouts with colleagues or students.
Google+ allows you to share beyond the 140 character limit of Twitter, but doesn't have as much of the games and junk as Facebook.
Like any Social Media network, part of the success depends on who you connect with. Here is a list of 50 Google Circles for educators to join.
Social Media in Education - connect, share, learn, communicate and more