Footprints

A footprint is basically a search string you put into google.  It will help you find websites related to your website that are willing to allow you to drop a backlink.

A footprint is a way to quickly discover similar websites. For example, many WordPress websites share similarities that allows you to quickly find them with a well crafted google search string. Using a combination of your keyword and a good footprint you can find wordpress blogs about your keyword that allow comments. The purpose of doing this is to find good backlinking opportunities.

Here are some footprints I've figured out.