I think it's less about it being a fad and more about it passing the ethical sniff test. If you end up working for an unethical company, a small error can blow up into a crisis because you were already dancing the line.
When I look at my Facebook news feed, my relatives who don't have a lot of money to throw around use Facebook to post baby photos and talk to their friends. They use Zynga to spend their (little) money on virtual cows/rows in a relational database. Both of these are mindless ways to pass the time, but only one of these should obviously raise red flags as something you should not want to be associated with.