I tried it several times, but IMO it's not worth posting lengthy and informative answers (to get the best answer) just to get like 20-30 visitors.
I've received over 30K visitors in one month alone from one answer. As the traffic was targetted, it was a good month. I still get about 60 visits a day from that answer a year later. It all depends on how and what niche you answer in. Timing helps as well for particular niches.
well you question get down and you wont get that much answer i dont think you can make enough money with these ways