It's late there I guess.....;)
[edited by: RedEyes at 12:08 am (utc) on Sep. 26, 2002]
Pink is for girls, blue is for boys, green is for good luck, and I won't say what yellow and orange are for, but I'd be pretty embarassed if my ad came up one of those colors...
Every time I hit refresh the color changes on my sponsored listing. Can Google's über-algo now tell that I'm a hermaphrodite?!?!
<keeps hitting refresh and buys a lottery ticket when the listing comes up green>
For example, neon green seemed to attract males ages 12-24, but was unsuccessful in other categories. Our agency decided to try this color as the background for a car dealership promotion flyer, and the results for this campaign were higher than other flyers. Of course, there were many other factors taken into consideration which makes this comparison difficult to prove (as in most advertising studies).
I don't know whether the effect of color would transfer over to advertising on the web, but it sounds reasonable. Some consolation is found in the randomness of the colors, which gives equal advantage to all.
Alternating the highlight color of the ads could remove any Searcher Bias (ie: imaginary figures: 30% of users will click the red ad 4 times out of ten, while 60% of users may click the blue ad 4 times out of 10; the Searcher doesn't know s/he may have this bias) towards a particular ranking because of its color.