When I kept seeing this happen over and over again by intelligent, high-level marketers, I realized that it wasn't just the result of someone simply trying to make a "fashion statement" by going against the grain just for the sake of it. But rather, the decision was based on months of testing and consideration of all of the pros and cons involved. I finally stumbled upon a video by Ryan Deiss that confirmed my suspicions and gave real, solid proof and justifications for him joining the bandwagon, making the change to his sites, and therefore being rewarded with instant opt-in increases of 5-8%. Kern also made a vid, but this one's a little bit more detailed... and still only 5 mins brief.
Hope you find it useful.