This maybe completely off the wall but since the whole point of the site is viral and to reach 1 million visitors why not let the visitors be the ones to put the content? You could have a "wall of fun" or something as such and let the visitors sign there name, in a graffiti type of way. I realize that this may not be the best for SEO but since you are relying more on word of mouth than anything at this point will it really matter?
VERY, VERY FUN PROJECT. GOOD LUCK! The site looks nice. Just stay strong. Persevere even when you've gone months with only a few hundred thousand visits a week. I'll be happy to help anyway I can, just PM. I have a blog here http://jameseo.com that gets some visitors..
SEO is the major tool needed to achieve this target...........my wishes to succeed in achieving your aim..
I created a site for a lost child and had 1 million hits in 2 days.....We found the child on the 4th day....So 1 million hits is not impossible....I wasnt trying to make money with ads or anything my only interest was to find the child
Wow - well done - what a great cause..... how did get such a large amount of traffic in 2 days? Do you have a link to this site?