Sorry to add to this discussion so late, but when I had my first baby in 1989 we were told to feed 10 minutes each side, and his poos were always green. He cried a lot, too, in the evenings, which I think was colic. I started bottle-feeding at 3 months, then stopped breastfeeding at 4. The crying stopped then, don't know if they were related.
When I had my second in 1997 (almost 9 years later) it was then completely different, more like today. The advice was more along the lines of feed on the first side for a long time, and only if you think you might have run out change sides, or that sort of thing. Anyway, I decided to only feed on one side each feed, and she fed for ages as she used to fall asleep and feed in her sleep. She never took a dummy or sucked her thumb, she always just wanted me, so I breastfed for 2 years!! Her poo was always yellow or even orange until I started weaning. I read that the longer you keep feeding on the same side, the richer the milk gets. It also encourages milk production, of course.
My third didn't seem to poo at all, poor thing, despite weeks of trying and resting and feeding almost constantly I didn't seem to have any milk (at least not enough, or she'd have died- but she failed to gain weight), probably because she was premature. Totally different subject, I know, but virtually all books and magazines fail to prepare you for this, presumably so as not to encourage you to give up too easily.