Just a couple of important notes...
phil hunt wrote:
Has anyone contacted Google to see what they think of opt-in adverts?
I would like to discourage people from contacting Google directly on our behalf. I have an existing and substantial (to me!) business relationship with Google and good contacts within their ad syndication group. It will baffle them if random people call them up asking questions about us.
However, Wikipedia is quite a high-traffic website, which would probably give it a reasonable level of clout in any negotiations with Google.
Sure. Even with Bomis, we don't just sign up for their general public program, we have a (long and detailed) contract. There's no reason to assume that their general AdSense terms of service would have much to do with us.
At the same time, I think it is important to recognize that "opt-in" is likely to be frowned upon for exactly the reason that you mentioned -- the audience of people opting in would be too likely to click just to generate revenue, as opposed to clicking out of genuine interest. That's useless for the advertisers.
I also am not really comfortable with opt-in. Compared to opt-out, I think it would generate very close to zero revenue. Probably less than 5% of the revenue potential of opt-out. The reason is that the vast majority of our pageviews are from people who just happen in. These people are not opposed to advertising, but at the same time, they will not care enough to bother to read a link about how to enable ads.
So with opt-in, we get almost all of the "negative press" issues as we get with opt-out, but we also don't get the kind of money that would enable us to do really astounding things consistent with our charitable mission.
Let me state again that I am currently opposed to any advertising on Wikipedia. I have only been talking about this because I think it is important for us to continue to make the "no advertising" decision while being fully cognizant of what it is that we are turning down.
It's much easier for us to say no when we imagine that the revenue would be $1,000 a month. It would obviously be much easier for the community to say no, if the revenue was to go to a for-profit company. (Hooray! The make-Jimbo-rich fund! Not.)
But I think that the issue really only gets interesting when we start talking about really vast sums of money that would be spent with extreme efficiency to further our charitable aims.
--Jimbo