Everything offline has a value, which is usually far more easily gauged than a digital product. The fun begins when the two collide and you have an offline offering for an online product, be it a site, a vid, rep work, FB or Titter account work, or any of a long list of things.

Having your information together when going to get a client is a great idea.
One method I use is to have a list of sites and information on comparable sites. If I am going to hit auto dealerships I get...