Forums can be real money and time eaters that bring in very little business while costing plenty. I see why you need to apply your energy towards what pays the bills.

Forums might help bring in a few customers for lessons, but your Dolphinstreet/MasterGuitarAcademy emails and websites likely work much better. Your past youtube lessons may have helped as well.

I've seen the ebb and flow of various forums and The Fret is no different in that aspect. People's lives and interests also ebb and flow. We haven't seen quite a few past "regulars" post in a long time. What makes or breaks a place is the interaction, frequency and content of member postings. The continued growth of social media like facebook probably impacts forums the hardest.