No reason for any surprise or conspiracy theories. 1. You visited a site that had "pizza" all over it 2. The page drops SIXTEEN cookies, including all popular

No reason for any surprise or conspiracy theories. 1. You visited a site that had "pizza" all over it 2. The page drops SIXTEEN cookies, including all popular ad networks: Criteo, Vizu, SkimLinks, Quantcast, and Google's DoubleClick. 3. For the next couple of hours (or whatever duration specified by Domino's media agency), pizza ads will follow you everywhere. While Skype may be parsing your chat to detect keywords, this would be complicated and potentially against their ToS. Using your browsing behavior is simpler, and a lot more precise. If you're worried about privacy, you should protect your browser in the first place. Start by forcing the Do-Not-Track option, then install Ad Block, and opt-out from all ad tracking networks [1]. Or simply use Incognito mode. Companies can still use IP and browser fingerprinting to uniquely identify you, but that's more work and not portable across ad networks. Not worth the effort for them, just to target a bunch of HN-ers. [1] http://www.networkadvertising.org/choices/ http://www.networkadvertising.org/choices/