Evan Williams mentions a poll on Kuro5hin about text ads. The top thing people want is to be able to make comments on ads. Evan's thought about this, I think it sounds like an amazing idea. Imagine people being able to comment on a product or service they used when they saw an ad for it. My guess is you'd get a lot of extremes, people who either loved or hated the product. I think it would be great to see an ad and be able to instantly know what people think of the product/company.
Would it make a difference? I think it could. It could have a few side benefits, the least of which is letting companies know what people think of them. It could be quite beneficial. At least until companies started adding in comments of their own to praise themselves (but there has to be a way to work around that.)
