eclipse has a usage data collector framework. we didn't want to use it since it's UI is not convincing and since we wanted to report with Google Analytics and it's superior analyze capabilities.
We have for now the number of installations. The next step is to know what users actually use. The eclipse epp data collector already features monitors for commands etc. and is capable of reporting the components that are actually used. By hooking into it we could benefit of this with very little effort.