with so many private trackers out their its nice to see new features and or add-ons being made. Because it gives a user more of a reason to use that tracker.
it also lets you know that the staff there are not only working to improve their site but also want to make your experience as a user even better.
for example, Oink has a add-on called oink-plus(user-made) where once installed using grease monkey for Firefox you can not only listen to a group before you download but it has similarlar artists, bio and pictures.
Another example,TTi has a movie a day also up until recently a movie or pack a week. Both are free or with 2x or 3x upload.
this is just one example on two sites.
tell me your favorite feature or features, and why?