" ... Kelp is a framework for taking notes about source code files in a simple way. It is composed of a set of command line tools, and a text file format. The text files contain annotations and can be written using any standard text based editor. The tools retrieve the annotations using a sophisticated search pattern.

Since annotations are stored separately from the source code module they describe, Kelp is a natural fit for annotating third-party libraries. When it is not possible, or desirable, to insert clarifying comments into code that could be replaced/erased by the next release, Kelp succeeds at keeping your annotations current and pertinent. ... " Possible wikispammer, but interesting enough to check out