Re: Seen similar comparisons before
Here are numbers from one person:
You can reasonably expect that when you begin commercializing a free site, some people will complain, depending on how you do it. I launched this site in October 2004, and I began putting Google Adsense ads on the site in February 2005. There were some complaints, but I expected that  it was really no big deal. Less than 1 in 5,000 visitors actually sent me negative feedback. Most people who sent feedback were surprisingly supportive. Most of the complaints died off within a few weeks, and the site began generating income almost immediately, although it was pretty low  a whopping $53 the first month. If youÂd like to see some month-by-month specifics, I posted my 2005 Adsense revenue figures earlier this year. Adsense is still my single best source of revenue for this site, although itÂs certainly not my only source.
http://www.stevepavl...y-from-your-blog/
And it's not necessarily intrusiveness. People naturally look at things on the top and left of a page (well, left-right top-down languages, I'm sure). The comparison I can't find talked about size and obnoxiousness of the ads didn't really matter. Contextual relevance and position did.
Regards,
-scott
Welcome to Rivendell, Mr. Anderson.