He said user content so that might be users uploading images, audio, or video with the associated storage and bandwidth costs not to mention workers for generating thumbnails.

I'm the grand-parent poster and not the parent, but yeah, my user-content sites don't cost anywhere near that much. Storage is probably the biggest cost, and that still doesn't cost much. I'm not really sure how a site like that could cost that much unless you're getting absurd amounts of traffic, or are using some poorly optimized software; though I also don't know the nature of the site or the content.

If my costs were anywhere close to that I think I'd have no choice but to suck it up and place some ads as well. As it is, community donations cover our costs just fine, but pretty much 100% of that revenue - which is all of our revenue - goes to infrastructure cost. We don't make any profit, but that was never the intention when creating the sites.