A great list of engaging scientists on Google+ (ok I'm biased a bit here since I'm in the list and I co-moderate the group creating this list). But for me Google+ is my Science Social Network. My feed is full of Science and Math and Computer Science. I'm sure it's possible for Facebook and Twitter to be set up this way but the Science community on Google+ is much bigger and the tool allows a greater amount of  in depth discussion that is necessary for talking about real science. If that sounds good to you then consider adding  a Science People circle starting with this list and joining the Science on Google+ community.
https://plus.google.com/communities/101996609942925099701
Science Engager Circle 9.1.13
Over the last two weeks, many individuals and pages associated with the Science on Google+ community (http://goo.gl/uhJCN) have been discussing recent projects and brainstorming about possible topics for upcoming Hangouts On Air. We took all of the individuals and pages that contributed to this discussion and put them into this shared circle. You can learn more about the individuals in the shared circle by viewing and contributing to this discussion: http://goo.gl/g6RYg4.
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