Actually you're both wrong - the number on the main page refers to the number of replies to the original message, not the number of posts - therefore Saviola got the historic 500th post in the thread, and you posted the 501st, Shaker!
Actually you're both wrong - the number on the front page refers to the number of replies to the original post, not the total number of posts in the thread. So Saviola got the historic 500th post, and Shaker merely got 501!