rlange - 6:04 pm on Apr 12, 2012 (gmt 0)
How do they determine "NOT PROVIDED" on search queries?
How many Google products do you use?
How often are you logged in?
How many of your websites are included in your accounts?
Surely the company that controls all this and so much more... it isn't too much of a stretch for them to develop footprints using your online activities.
I think you're implying that if I did a Google search for [link sellers] or [linking schemes], or had an email conversation using my Gmail account discussing linking schemes, all while having my website in Google Webmaster Tools or Google Analytics, and then Google notices a sudden increase in links pointing to my website, that they could reasonably determine that I am responsible for those links.
It's a logical scenario, but it's also based on no evidence that I am aware of, nor have you provided any in support. It's 100% speculation. Even worse, it comes off as a "Big Brother is watching you" style conspiracy theory. I don't think it currently qualifies as a valid explanation.
Edit: Also, I hadn't looked into the issue in any detail, but as far as I'm aware, it's never been confirmed (at least publicly) exactly who was responsible for J.C. Penney's spammy backlinks. That they didn't continue after the firing of their SEO company is a pretty good indication, but that's after-the-fact. If Google penalized them based on an accusation, that's a bit frightening.