Just my observation - seems like there is less listed on AG

U S Audio mart has certainly progressed in the last few years and the buyers as well as the sellers have all upped their game, with that said I still use Audiogon to buy and sell when needed as what they offer is unique and on a larger scale, plus the forums are great to read and reference when needed. I do pay the $50.00 membership to USAM to give back for the free ads, which I have used quite a bit lately. Enjoy the music

USAM  Much easier to use. Communications between seller and purchaser is great, and it's free. Post all the pictures you want. It's great for our hobby!  Can't beat that.

Could Craigslist be a major reason you see fewer online AG listings?  

Doubt it

CL has been there since the beginning

I’m more inclined towards buying/selling locally nowadays due to the high costs and risks associated with shipping. Audiogon is not friendly towards local transactions. I might want to see or hear something before I agree to buy it. I might be happy to buy and pay through AG then pick it up in person. AG makes it difficult and frustrating to communicate with the other party and I resent the way their system makes accusations and blocks my ability to communicate with a seller even after the sale is complete.

The only saving grace is that Tammy is a gem and she gets things figured out quickly.