From Let's Sermo I get 400$ per month from private ads.
I have not really monetized it, in fact for this month I have removed the ads as I am recoding the sidebar.
From The Dollar Diary I did get one affiliate sale and some private ads.
On one of my older sites Aviation Earth I had got a big offer of 500$ per month, but I was lazy to edit ALL the pages of the site as it was not on a CMS. I was 13 then.