I wanted to write a much longer post about this than I am going to tonight, since it’s late – but I’ve noticed that many of my posts, recently, have been retweeted 30-40 times per post – sometimes by the same people, but oftern by different people.
For example, my post on SEO, Web Analytics and Social Media have Merged was retweeted by my followers 35 times over the period of a day and each individual can reach others in their own networks, so a lot more than the 35 people who initially viewed my article from a retweet may have ultimately seen my post.
Because tinyurls are used a lot of the referral traffic might not show up in Analytics, though I believe there are other ways to track information.

