I'd say, until the site generates AT LEAST 100K unique visitors per month... focus on content, etc. Don't bother w/ the ads atm! Traffic = revenue, but ONLY in strong numbers! Ads, too early, will just annoy people to go somewhere else, or they'll just create a competing start-up, and you WILL start to see a decline in growth. Again, ads are a smart revenue source... it's just not the right time, imho. Focus on GROWTH... and, so far you've been playing your cards right. Don't make a mistake now!

Atm, this site would probably qualify for the ads that generate revenue based on "we pay you IF a vistor clicks the ads, then buys something from our site". Think about the last time you were visiting a site, and actually clicked on an ad and bought something? I personally can't remember a time I ever have!

Again, in my opinion, let the "boxing" crave set in a bit more... and focus on content. People are coming, and the site is getting bigger. I, personally, am promoting the site w/ every person that inquires about boxing. And, I know from reading here... others are as well!