rowtc2 - 7:08 pm on Aug 26, 2011 (gmt 0)
Sorry for late reply. I've just got a job as SEO manager in another city :P
I am thinking Google recognize addresses, contact forms and why not newsletter option available.
It can track user activity on site after click on a result. So Google could count if user has subscribed. Can be used as a sign of quality site (related to Panda).