I can remember once repping someone because I wanted them to rep me back... and it never worked.
Want to hear more? I repped
alatar who had praised my new thread in his first post on it, and I was like "nice that you praise it, but can't you rep it if you like it?" and then I went to rep his post just to give him a nudge. Okay, I was considering repping it anyway, but I might not have repped it had I not had this extra reason.
But you see, it did not work, I learnt my lesson.
Admittedly, these days when I rep people for some threads I have also participated on (books discussions, RPGs, ww games, paper telephone, whatever), of course I hope they will rep me in return. But it's not definitely the reason why I rep them. (If getting rep back was my motive for repping, I would not rep people as much as I do. I give out far more rep than I receive, but I don't complain.) And of course there is the psychological basis (I swear I don't intentionally abuse it even though now it must sound like that
) that if you rep someone very often, they are maybe more inclined to consider your posts rep-worthy. I know I rep people who are generous with their reps more generously than those who are not. It's subconscious.
I've also asked or hinted that people should post on some threads, but rather seldom and not forcefully at all. So I'm not sure if it counts.