I'm not always nice, but when I am, my reasons for being so are generally:

1. Ego. Yeah, I admit it, I like having a high rep. I don't care about every individual point or badge, but it would be a ridiculous lie if I said I didn't pay any attention. You don't get votes for being a jerk.

2. Quid pro quo. Occasionally I have questions, too. Having a reputation for helping others (and I mean this in a qualitative sense now, not a mathematical one) tends to get people to pay more attention to your questions, and be less judgmental.

3. Learning. Sometimes I have to do a little extra research to answer questions, but I benefit from this process too, so it's not just me being "nice." There have actually been a few times when I've gone back to one of my own answers to help me with a current problem!

4. To help stay focused. If I'm sitting around waiting for a 20-minute process to run, or for some e-mail to arrive, answering some of the softer questions is a pretty good way to stay in the "zone." Particularly when the alternative is basically killing time, surfing the web or chatting people up near the coffee machine, that sort of thing.

People think of posting as a form of goofing off, but I don't think that SO has really changed my number of productive hours, it's just replaced the already-unproductive hours with something slightly less unproductive. And when I'm able to get back to my task, my mind hasn't turned to putty, so I consider that a net benefit.

Altruism doesn't really factor heavily into it. That's not to say I never just want to help somebody - I do, but that's not reason enough to spend the amount of time that I've spent.

I'm not always nice, but when I am, my reasons for being so are generally:

1. Ego. Yeah, I admit it, I like having a high rep. I don't care about every individual point or badge, but it would be a ridiculous lie if I said I didn't pay any attention. You don't get votes for being a jerk.

2. Quid pro quo. Occasionally I have questions, too. Having a reputation for helping others (and I mean this in a qualitative sense now, not a mathematical one) tends to get people to pay more attention to your questions, and be less judgmental.

3. Learning. Sometimes I have to do a little extra research to answer questions, but I benefit from this process too, so it's not just me being "nice." There have actually been a few times when I've gone back to one of my own answers to help me with a current problem!

4. To help stay focused. If I'm sitting around waiting for a 20-minute process to run, or for some e-mail to arrive, answering some of the softer questions is a pretty good way to stay in the "zone." Particularly when the alternative is basically killing time, surfing the web or chatting people up near the coffee machine, that sort of thing.

   People think of posting as a form of goofing off, but I don't think that SO has really changed my number of productive hours, it's just replaced the already-unproductive hours with something slightly less unproductive. And when I'm able to get back to my task, my mind hasn't turned to putty, so I consider that a net benefit.

Altruism doesn't really factor heavily into it. That's not to say I never just want to help somebody - I do, but that's not reason enough to spend the amount of time that I've spent.