I am hearing what everyone says about charging to advertise and to be honest, it has been something I am been thinking about since I took over the forums. The main reason I haven't just turned off the setting and opened it up to everyone is that it would be unfair to those who had invested to be subscribers/power sellers and Sponsors and I am not in a position to refund all who had purchased those accounts.
I am happy to wear the cost of the forums as its a resource for all of us and like I mentioned earlier, I am not in it for the money. And if it helps, every dollar I have got so far from those supporting APS has gone into getting all the licensing and add on products up to date and all future funds will be used for improvements.
Anyway, that's some Friday morning input from your local site admin