It's tough, because as barret openly points out, very often the motivation is a selfish one. So if you're doing it because it's going to help your team vs. simply being generous and helping someone else, where do you draw the line there?
Personally, I'm OK with this kind of communication being part of the game. On numerous occasions I've given advice to conference mates during recruiting (almost always solicited by them), usually regarding if I thought a player they were thinking about going after was good, or who I liked between two players they were considering. Is that taboo as well? I would really hope not.
(That last part also speaks to the community building referred to above. That's more of a DII/DIII type thing and helping a relatively newer coach ... can't recall too many times where gillispie or OR needed my confirmation on a player, lol.)