Stairway Software's Internet Config tells Squirrel which application to load when an item is double-clicked. For example, double-clicking a newsgroup item will load your preferred news reader. Squirrel also uses Agents to track the items in your information farm. These Agents are like mini-search engines that operate on your own farm file. They aren't going to go out and hunt down new URLs for you, but they do help manage very large farms with many entries.
Agents are the most confusing piece of an otherwise simple program.
Users with no knowledge of Boolean Operators are likely to be daunted by the AND, OR, NOT commands of Boolean logic. The documentation does a fairly good job of explaining how these things work within Squirrel. Anyone who has used the advanced commands available in search engines should have little trouble configuring an Agent in Squirrel. Again, the Agent function is powerful, though not likely to be of interest to people with relatively small collections of URLs. The Skinny Eastgate's Web Squirrel is a wonderful tool for people with large collections of URLs.