[Erik, I deleted one of your posts because you double-posted by mistake].
One question which occurs to me, and which is probably the most pertinent to current PDF publishers, is how to combat the growing glut. Over the last year, sales of any given product have halved (that's a rough figure), and as time passes, they'll get less.
One thing to do is make sure you put out more products. I'm aiming at one a month right now, and total sales are still much the same that they were when I started with Wild Spellcraft all those months ago. But I can't go any faster than that, because in the current market, I'll just be competing with myself. Eventually, I'll have to change strategy again.
So, what can we do to increase sales on individual PDFs? here are some thoughts:
1) Try harder to "legitimise" PDF products. They are seen as more legit now than they were two years ago, and that will hopefully improve. Unfortunately, with the "glut" comes a large number of low-quality products, which can help to reduce that legitimacy. On average, with so many products available, the chances that the buyer will pick up something shoddy is much higher.
2) Does the fact that RPGNow pretty much has a monopoly make a difference? [Sorry, James...]. RPG.net tried to do the same and failed, and SVGames currently charges 50% or so on electronic sales, which kinda prices them out of the market. The other option is to sell them yourself, but then you lose RPGNow's publicity factor - that will matter to some less than others, of course. I've been in two-minds about it for ages.
3) How could info about PDF products be distributed better? How can we make sure that people hear about the good ones?
I'm sure there are other factors which escape me for the moment. But it is somethng which bothers me, having seen my own figures over the last 18 months. I feel kinda sorry for anyone joining in now - they missed the heyday.