From the LonelyCache About Page:

LonelyCache is dedicated to showcasing lonely geocaches, the geocaching trailblazers that hide them, and those geocachers that seek them out. A system for rating lonely geocaches is at the heart of this project. This will allow geocachers to identify those especially rewarding geocaches. Statistics are compiled and presented using the rating system and are used to create various leader boards highlighting lonely caches, hiders, and finders.

In order to accomplish this, LonelyCache utilizes a geocache scoring system pioneered by the DeepSouthwest Geocaching Project (DGP). With this system, geocaches with a lower find rate are worth more points than those found more frequently. Geocachers accumulate points from the scores of the geocaches they have both found and hidden.

Several different leader boards are kept based on geoachers' accumulated points. These leader boards are kept for different geographic boundaries. Currently, LonelyCache completely covers the eleven United States of Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming. It also covers the western portion of Texas between New Mexico and Mexico. LonelyCache is further broken up by Counties and DGP Regions. The DGP Regions are based on the Deepsouthwest Geocaching Project's region boundaries. So there are leader boards for LonelyCache wide, each state, each county, and each DGP region.