Why, and how, ads follow you around on the web
If you've noticed lately that certain ads seem to follow you around, and are wondering why, I think I can help explain.
Take a look around this blog post at the ads. They're placed by Google, and for the most part they are targeted to be appropriate for the content that I write here. For example, if I mention dachshunds here, there will be ads for dog food at a certain point. And that's because this blog is read by "bots" (short for robots) which search for words and figure out what seems to be appropriate for the context of the page. Which, of course, means that the more I mention dachshunds, the more the bots will think that I am writing about dachshunds, which I'm not. Writing about dachshunds, that is.
But that's only half of what makes the ads on this page more appropriate for the person reading it. The bots are actually watching you, kind of the same way. So if you visited, for example, ebay, and looked at dog food for dachshunds, ebay sets a "cookie" on your browser that essentially says that you were interested in that particular item. You don't have to buy anything, you just have to look.
So when you visit this blog, for example, wondering why and how ads follow you around, an ebay ad for dog food will probably follow you there. That is, if you have recently been on the ebay site (or whatever sites use this kind of stuff).
Personally, I don't mind all of this. The bots help me to find local stores, they help to give me directions to places, and overall, I am flattered by their attention. I have no objection to the bots knowing that I own a dachshund, and I buy stuff for her. In the bad old days before this type of sophistication, advertisers just threw everything to everyone. I would see ads for things that were, uh, not applicable to my gender. I still get a lot of stuff like that in email, which goes automatically to my junk folder and I throw away with barely a glance.
All of this is called "narrowcasting", as opposed to "broadcasting" advertising. Broadcasting, as the name implies, just means throwing a whole bunch of stuff randomly out there, as if this was 1955 and we were all watching network TV.
Posted by Brad Hall