The Census of Science Bloggers 2011 asked, Excluding search engines, what is your primary traffic driver? After eliminating for single instances and some standardization, the breakdown is as follows: Twitter (70) Facebook (59) Links from Other Blogs (45) Reddit (14) ResearchBlogging (13) Feed Subscriptions (10) Google+ (8) Commenting on Other Blogs (7) Science Blog Network (7) Return/Direct (4) StumbleUpon (4) Tumblr (3) FriendFeed (2) LinkedIn (2) MetaFilter (2) Gee. Twitter and Facebook top the list. What a surprise. Well yes, confirming what we already know isn't that useful (unless you're not already syndicating your content to Twitter and Facebook). But keep in mind that this is a list of primary traffic drivers, which means that each site on the list has the potential to send you more traffic than any other source. The trick is knowing how to tap that potential. What are we really talking about then? Because there are trade-offs in time and energy, a...