Another good example is the ingimp project, where an instrumented version of the open source software GIMP was created. This instrumented software collects certain types of event-based usage data, such as the commands that are used, user interface events, and users’ own (optional) descriptions of their tasks. The resulting data set is made publicly available and serves as a basis for usability improvement efforts in the open source community.

I like the fact that they care about privacy and make very clear what kind of data is recorded. After all, you can download it and look yourself!