100% yes, have been wanting to pay/donate towards the project for along time. you spend a lot of time making this program, and deserve to be paid.
one thing i wouldnt want though, is to go the direction of newsleecher.
seems spiril spent a LOT of money on an expensive copy protection system, which by iteself introduced a massive number of bugs, problems and cpu load. (yet was still being cracked same day it was released) and cracked versions had less bugs
it was for that reason i ditched my NL license & jumped to altbinz.
if you could keep the protection relatively light (it would be cracked anyway no matter what you do)
but have some form of user id, that gives it benefits, such as support
(if you want support in forums & irc, you need to state your user ID)
auto updates etc, needs User ID...
also may be worth having a free version availiable? limit its use, by disabling features like scheduling/rss/search's
i am always 100% into donating to worthwile good projects, but 100% against copy protection systems that make life easier for cracked users & harder for the paying customer.
you have a very good relationship with the people around you, always listening to comments and implementing fixes and features, this by itself makes people want to donate, not only have you created the best usenet utility ever, but you also show that you are interested in bettering it.