Get a YPN advertiser account and look up the top keyword bids on the terms you know are being clicked in your parked account using the traffic analysis feature...you can guesstimate from here the % paid to parked.com from Yahoo and then to you, the domain owner..not an exact science but you can quickly see that when sedo is getting a nice cut of a $10/click name and you get a .15/click or even a .50/click something is very wrong..that same click at parked might pay you $2+ off the top of my head...again all just estimates here and it all depends on many factors..