about warming up and stretching

I hear it's good to warm up before a workout and great to stretch aftwerwards. But since it seems implausibe for any person to have grown up in the western world without hearing about this, I haven't brought it up.

personally I just put on my shoes and go, jogging very slowly for the first few hundred meters. That's my warmup. I think real athletes would not approve. Then post-workout I do some stretching, if I remember.

should you stretch or not stretch? you decide!

(http://running.about.com/od/running101/a/stretching101.htm)