Mary says that she did the "Thinking Visually" logo used on this piece posted publicly on Craigslist. She told me this personally, after I called her expressing that it was something I produced. This kind of thing is bound to happen to individuals and brands everywhere. If your stuff shows up in a Web browser, it's likely to get used in ways you didn't intend. That's just a reality of the space.
So I'm putting my faith in the buddy system vs. the legal system on this one. Let's give Mary the benefit of the doubt and assume she created the logo and it's a sheer coincidence. I originally posted the logo here over a year ago. The date is there and everything. If she wanted to clear her reputation, she could do the same thing on her Website. After all, it says "please don't steal" right on it.
In case you're wondering, the visuals I produce here and aggregate here are for you to use in your presentations, sideshows and blog posts. They are meant to be a resource for you. A reference is always appreciated. But if you're going to say you did it yourself. I'd ask you to prove it.