Customer overlap and keywords

Eric Goldman recently singled out this passage in the UMG v. Veoh case:

50 Cent, Avril Lavigne and Britney Spears are also affiliated with Sony-BMG, which gave Veoh permission to stream its videos by these artists. Furthermore, even if Veoh had not had such permission, we recognize that companies sometimes purchase search terms they believe will lead potential customers to their websites even if the terms do not describe goods or services the company actually provides. For example, a sunglass company might buy the search terms “sunscreen” or “vacation” because it believed that people interested in such searches would often also be interested in sunglasses. Accordingly, Veoh’s search term purchases do little to demonstrate that it knew it hosted infringing material.

So, can you purchase unrelated keywords if your customers overlap?  ABC Family evidently thinks so, according to my Gmail ads:

 

PLL, incidentally, is Pretty Little Liars (which I do watch with great enjoyment).   I don't know how I got targeted on Harry Potter, though, since it's far from my fandom.  NB: I can't exclude that ABC's licensing agreement with Warner Brothers allows this kind of cross-promotional advertising, but that's the kind of thing I can't imagine consumers knowing much about.  "If you like X, you'll love Y" is classic comparative advertising.  Even though I'm not sure that if you love Harry Potter, you should watch the winter premiere of Pretty Little Liars.