I visit a number of sites a heck of a lot less because of the fact that some people feel like they have to cripple their feeds by showing only a snippet. Specifically this irritates the hell out of me:

Come on Ars, and the rest of you jackasses, put all the content in the feed. You can put a little ad IN the feed if you must, you can still track the "hit" and any clicks to/from each item, etc. On some devices your website sucks ass, and even when on a full machine with a completely capable browser there is no reason I should be forced to click out to "read more," man that's annoying. The end result, I just don't even open said entire feeds as much anymore - next.
Comments
I second that...
I find it interesting watching this whole mechanism evolve. Seeing sites still fight for control in an information overloaded state is pathetic. I think of myself as a light weight in this RSS information age and even I can't ever get my unread items in my reader under 1000 unless I just start marking threads read so they go away. Moving up on my priority list (now above finding new feeds) is eliminating feeds so things I really care about don't get lost in the noise. Any site that hides information from the feed actually pleases me cuz it makes it so easy to hit 'Unsubscribe' - one less bundle of unread items to muddle through.