We paid our authors, columnists, and bloggers. And paid a staff of 2.5 full-time employees and a salesperson. Add benefits, insurance, rent, hosting costs, and taxes--and you're not looking at a lot of profit left over.
That's the sad thing: you're saying that it still turns a net profit after paying all of its staff and costs, and yet that's apparently not enough to keep it running.
Personally I would do like RailsCasts.com and ThatGuyWithTheGlasses.com (now ChannelAwesome.com), two sites I frequent, did... offer pro accounts.
Pro accounts could:
1) remove all advertising from the site.
2) have access to content early like drafts of upcoming articles
3) have access to revised or updates to articles
4) allow people to recommend articles
the list could go on, you'll probably think of a thousand things that I couldn't since I'm not in marketing.
At first, I was wondering why not just sell the business?
Who knows, you might have tried? After thinking about it some more,
since it's your baby--why take the chance of letting some
with more money than taste/knowlege blow it up? I understand your
decision to close it down. I hope you keep talking about
the efficacy of Internet advertising--the real truth. I'll
follow you on Twitter.