When discussing marketing and product strategies, I sometimes come across as a broken record! One of things I preach is the power of change. A button's color, an ad's call to action, or the placement of a marketing module can each have a profound impact on user interaction. Of course, the only way to understand is to test... and the only way to effectively test is to have proper tracking place (don't yet? try KISSmetrics). Here is yet another example of a relatively minor change that has had very significant impact. It should serve as motivation for web and product marketers to test, trial and iterate.

Facebook recently added a post-logout promotion for the Facebook iPhone app. Nothing fancy... and nothing that required real engineering effort:

The effect: in under a week, Facebook iPhone usage soared by 20% in under a week: