We created Timmy ( http://timmyontime.com ) more than 2 years ago and we recently reworked it a lot. There's a feature called "notes" that our own team uses a lot but a majority of our users don't use or understand it.<p>Notes can be used for many things. Example, we want to add a todo, we create a note like this : #todo @dan Use the new version of jQuery. We explain it in the app and in a post (see http://j.mp/vS7dK) but we don't see any difference in its use.<p>We believe in this feature a lot (at least, we're using it a lot). Any suggestion?
How much is "a majority" of your users? You've got to figure out whether it's a power user feature that's not relevant to everyone, or something that people either don't need or don't understand.
If your team finds it genuinely useful, it means you haven't conveyed the mental model correctly to your users. Have you tried sitting strangers in front of the software and seeing how they use it? Iterate on the interaction design until you find that it clicks in face to face testing.