That is a lot of traffic indeed. I know I'm very particular about keeping server load down as much as possible because it's hard to make money off of advertisements. Even with a highly optimized, custom server install with nginx instead of apache, efficient software, etc., hundreds of active visitors at once will make a dent in the server load. 
I'm interested as well. What was your niche?
I'm interested as well. What was your niche?
