I'll admit the MySpace to Facebook comparison was closer. However ... comparing Facebook to AdultFriendFinder? Either I don't hang out in the "right" Facebook groups or this is total bull. They are not even close to interchangeable in purpose, audience nor function.
I suppose the reason I find the concept of this article sad is that we're moving to a place where instead of an expectation of privacy ... we now have an expectation of no privacy. I post photos, sure, and status updates and events. But I'm careful about the permissions on them and I don't post EVERYTHING nor will I. If that makes me suspect, well, I guess suspect me. But it -should- show I have a reasonable level of intelligence on what I keep private.
While I do use Facebook, I have a number of friends, neighbors and co-workers who do not. And I don't consider them suspect. Why would I? I don't go "oh, my neighbor is always frequenting that gaming site but refuses to use Facebook, he must have something to hide".
I also have a number of friends who either maintain multiple accounts (because they hate dealing with permissions) OR keep their account obscured so that you have to know that it is their account (different name, odd profile photo, different email account, etc). Purely because we ALL have people in our lives we don't want to know EVERYTHING. Is that the next step for being suspected?
Glass walls. You don't want them. At least not until everyone in power can give up their judgements about peoples' personal lives.