I used too all the time but then one individual ruined it for me. Some girl friended me and then begged me to donate to her. She was questing an item for her dream avi. Rather then giver her the gold, I thought I would be nice and outright buy and give the item to her. You know what happened? The next day, she de-friended me, set her profile and pms to private and then SOLD the nice item on the MP. The NEXT day!! Questing my a**.stressed
EDIT: I donate to dumpster dive all the time. Too many junk items. XD
There are people who donate, they just don't usually publicize it :3 No matter how large or how small the donation is does not matter. Donating an expensive gift does not make you better or worse than someone who donates a less expensive gift.
I used to donate a lot more than I do now. I don't have the gold anymore (I'm sitting just above 19k right now that I have built up over a month) and people tend to quest items I can't even afford for myself, let alone someone else.