Regarding improving CTR, sailor's comments hint that the improvements may cause CTR to lower statistically because of increased impressions, while improving overall earnings.
There are many social media gadgets that can be added to a page. You can see them in action on many of your favorite sites. A gadget that includes a tell-a-friend function in addition to the facebook etc. stuff should do the job. I've added one of these gadgets and experienced an increase in traffic from sites like Facebook, with people sharing my pages from Facebook itself, in addition to the tell a friend sharing.
[edited by: martinibuster at 9:09 am (utc) on Oct. 26, 2009]