The short version seems to be "probably not anything malicious, but you might wanna change your lj password and delete some cookies just to make sure."
And let me just say that good grief, I had a ton of cookies built up from I know not where. A lot of them seemed to be from ad places, and I don't click on their shiny banners or popups, so I don't know why I had so many.
Oh, and, I'm usually so paranoid with internet stuff, so now I feel like a silly little sheep. Baaah.