This "test" is a bad idea on Google's part. The most reputable of the publisher's in the network aren't going to want Google adding their own branding directly to their sites without permission. Will serious and significantly-sized content publishers like newspapers or other truly unique content producers stand for this? My bet is they won't let Google get away self-branding and it will provide an opening for private-label ad providers to move in further. Publisher's will want to use ad-serving platforms that don't distract their site's visitors from their own hard fought branding efforts.

Personally, I don't mind it for the small-traffic site that I run a few ads on, generally-speaking, but even I might have to drop AdSense ads purely because the image doesn't blend with my ad space's background color.

Seems like a bad idea and Google will realize that they're being overly selfish with this move and it'll backfire.

Google performs these tests in order to see what types of changes can increase advertisement click-through rates. If, by seeing the Google logo, more casual surfers are inclined to click the advertisements, then it only makes sense to include the logo. Google's name is already present in the advertising area. Doesn't it make sense that having advertisements on your website is primarily to earn money for the space? If Google is testing ways to earn you more money for your space (and performing this test on only a small fraction of your traffic), should it really be seen as such a bad idea.

Perhaps, like with their toolbar or with their themed holiday units, they could provide a generic "opt-in" for testing such as this, to be sure certain advertisers don't jump ship. At this stage, though, it would make more sense as an "opt-out" since everyone has technically already opted in due to the complexities of the fine-print.

http://www.stareclips.com/?adsense-testing

I'm not sure why having a Google logo on my site would earn ME more money. It serves a purpose to Google's end by getting their logo out there on all types of websites, but it doesn't lend any credibility to the ads themselves.

Think of a company like (any major newspaper). If Google doesn't let them opt-out of showing the logo they are essentially grabbing free ad space.

More importantly, I'd suggest, that by highlighting the fact that these ads are supplied by Google they would make someone less likely to click on them. If I'm browsing some major newspaper in any city, I'd generally assume that those ads are relevantly placed there by people local to my newspaper's region. This isn't the case, often, with Google's national ad platform and seeing their logo might make me think twice about leaving the page I'm on to view an ad vs. an ad supplied directly by the local market there.

I know Google already shows their name - but at least it can be of the same color/font as other text/bg on the page (rather than rainbow colored graphic ext with a white background) thus it has more of a tendency to blend in.

If the world trusts Google's ad so much that having their logo there helps, fine, but I highly doubt they will find that to be the case and thus ultimately, from a monetary perspective, that is another reason this test will fail in addition to the fact that many publisher's will object.