Yes. you are right (your prior post). Among other things, etm records and categorizes time spent.
Are you getting it from the etm_qt site? I have ver 2.3.1, installed via easy install (easy_install -U etm_qt as root). That is best for now, until the updating slows down a bit more. Glad to see you plan on trying it. In fact, it was just updated from 2.3.0 within the last couple of days. The changes are usually minor and helpful, so just run easy-install every month or so. You will need mercurial as well if you start using etm regularly, as I do. All of this is explained on the etm site: http://people.duke.edu/~dgraham/etmqt/
PS Don't hesitate to ask your questions on the etm google site. https://groups.google.com/forum/?fromgroups#