I received an email from a reader in Canada who reported a popup for AntiSpywareMaster, which is actually a rogue program that tries to goad you into buying the software (which just serves adware, from what I find online).
They sent a screenshot of the page, with the popup, but it didn't show an ad with it. Rather, it displayed a bad local /tmp path for the AntiSpywareMaster. I have looked through the ads on the site and cannot find anything suspicious, nor could I replicate it by repeatedly loading pages.
This does not mean he did not somehow encounter it somehow via the advertising networks. It is possible, especially based on what I read about AntiSpywareMaster, that his computer is infected and causing the popup when he visits the site. However, I wanted to put out this message. I am continuing to investigate.
Please, if you encounter this, take a screenshot (if possible) of the page and email me.