I'm not allowed to disclose the site at this point sorry. I currently host them and been helping out with there site along the way, also been trying to gain as much as we can out of GoogleAd's with marginal success.
I had suggested selling ad space, so thought I would ask and see what would be the average price for a site receiving as many hits as this does.
Just to help with your estimations a little more the site is for a MSN Messenger Addon.
MSN messenger add-on ey... doesn't sound very niche, but you could definitely charge $XXX weekly and high $XXX monthly IMO. That may even be under price. Sites this large should definitely get a tracking system setup and test out a few different ad placements to determine the actual amount of clicks/mo an ad should recieve and determine a price off of that. Hint: Unspecific traffic usually is around $.04-$.08/click.
I have been given the go ahead to collect some actual prices for advertising, depending on what you want and for how much.
At the moment we have no idea for prices. But we do know that the types of ads would most likely be Text and 468*60 Banners ads with 5 in a rotation, still leaving your banner/text ad open to 18,000 uniques daily.
As I said before the site is for a MSN Messenger add-on, you can also have a banner placed in the today screen of the program when it starts up which is shown by most (aka 60%+) people who run the add-on.
I'm still not willing to give out the site address at this point, but you are free to suggest prices aka $200+ for a week for a banner etc...