Sometimes before... always after.

That whole article is focused almost all on improving muscle strength through stretching though, and debunking that line of thinking. I thought that had already been thoroughly debunked.

I don't stretch to improve power output, I stretch to prevent injury, because my muscles and connective tissue, particularly my ITB, piriformis and hip flexors are rediculously tight, which leads to improper patellar tracking, which leads to cartiladge and tendon irritation and inflammation which = sit out from cycling for a while. As a matter of fact, I had a PT recommend doing hip flexor, quad, ITB and piriformis stretches 3 times a day, regardless of whether I'm riding, as long as I wasn't too cold.

That and using the foam roller for some SMR has been a godsend.