Backstory for WordPress is a plugin by backstory that lets people add Backstory to their WordPress blog in only a couple of clicks. Signup at http://getbackstory.com
Backstory lets websites, of any size, personalize messaging, content and advertising in real time, for every visitor as they enter. In turn we help them increase engagement whether they’re looking for more page views, repeat visitors, likes, tweets or more, we can help.
There are free and paid for options