I do agree that he should place ads on the site to cover costs.
I've donated to the site in the past when I could as I like it and hope it to be around for a long time.
Although I do know that he'd have to sell direct ad space because a lot of content on there is unsuitable for adsense and many other ad networks.
But I do think he could make some substantial money from ads and I wouldn't mind if they're on there.
Like this site, it has ads and I don't mind them. Websites cost money to run.