There seem to be two camps on this. One camp is extremely helpful to other fly fishers they encounter n the water and another camp keeps their hard-earned knowledge to themselves and expects the others to learn the hard way.

I'm mostly in the former camp. If I encounter another on the water who asks how's the fishing, I'm perfectly happy to tell him how my fishing day is going and what fly seems to be working for me. If it is a fly I've tied myself and I have enough of them to see me through the day, I offer one or two to him.

But I'm in the latter camp when it comes to sharing information on what I consider to be a truly secret spot. If I have scouted out a remote stream that worked well for me and did not show evidence of any (or much) fishing traffic, I only share it with close friends - preferably ones visiting from distant states.