Aye aye I leave rep, not so much in the general chat section though (as it doesn't really count for anything). But if someone has a good helpful post I will leave them rep.
I rep in any category i am reading in. Even though it doesn't count for much in GC, I still love seeing that people like my posts in GC so I figure others like that too.
I leave good rep if I find something useful. I agree with twisty that giving rep in General Chat means nothing unless the giver has a full rep bar even then, it is like one point. I also give red when I find someone spamming or just dishonest. Of course, you will know if it is me either way because I always sign all my reps green or red.
People dont give me many greens (I dont attempt to be helpful) so I dont even think about/remember to give anyone greens.
I probably have left less than I have recieved even though I have gotten quite a bit of useful information here. I'll start leaving more I suppose.
Even though I am new here, i just figured out now how to leave rep duh, well cheers to all the good posters i see that deserve it