Well... don't get me started.. SEDO etc.. (its NOT just sedo) is taking a very large cut. Yes, I know, so is GOOG but there is nothing we can do about that....
I am a little different than most here. I am BOTH a domainer and a BIG advertiser on Google and Overture. I spent for ONE of my ecommerce sites $70K last month on PPC ads. I also have parked domains in the same genre and keyword range. ONLY because of this fact did I realize HOW MUCH THEY WERE TAKING.
Because of GOOG TOS I cant quote exact info so I will give ballparks, for a particular keyword, I pay 1.50-2.50 per click, SEDO was giving me 10 CENTS. When I realized this, I then decided to do something - I decided to buy a parking program, since there was none available (you can pay DNF to program one for each site for $50 each - a slow and expensive process since you also need to pay for hosting - but I have had one made and like what they did) I decided to get a parking template programed to my specs - for my use. (I will be offering to to others soon). In my preliminary testing I am getting .75 - 1.00 per click on the same site and same keywords (remember sedo was paying .10 for the same keywords). I also have pages that are optimized for my top keywords, and that I can build traffic to (through seo and linking) I don't know the dynamics of other markets, but I would think it would be similar. Yes, it is better than getting nothing (which is what I was getting not long ago) but collectively the domainers here are leaving a LOT on the table...
Just my HUMBLE opinion.....
Steve