For anyone interested in issues of privacy, I'm reading a great book, "Dragnet Nation," by Julia Angwin. And I found this interesting.
I was struck by this:
Professor Ryan Calo...points to a Stanford University study showing that an individual will respond more positively to a politician whose picture is subtly blended with his or her own photo. The change in the photo is undetectable, but it makes the viewer more receptive to the politician's message. "Now, imagine if a social network were to offer a comparable service, permitting advertisers to blend their spokesperspon with the user's own profile picture."