Last week I wrote about email as a vehicle to drive user engagement. Here is another good example from SlideShare. Earlier this week I posted a presentation on paid search best practices from a recent Dogpatch Labs event. That day the presentation made the front page of And they immediately delivered an email notifying me of the popularity. Its not a new concept (Digg for instance is great at this) but its an example of powerfully conveying accomplishment and driving engagement via email. And in this case (and in Digg's) their content rotates so frequently that is quite compelling: