Running: good or bad?

[sureshs]

To be frank, I run a little before playing tennis to warm up, and then I try to play singles as much as possible to make me run.

I picked up one of those free junk magazines to read during lunch and it turned out to be a racing and marathon magazine. In a sarcastic article, a writer wants a Bill of Rights for runners because of how they are looked at. Joking aside, one of his complaints was about people coming up to runners and telling them "Don't you know running is bad for your knees?"

Going by the number of people who seem to need knee and hip replacement surgeries while leading ordinary lives, why would someone increase the chances of wearing out your joints? Is running a good idea or a bad one? The magazine seems to be supported by advertisements from foot doctors.