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Google, Firefox, and Privacy - Jen's Sweetie and Code Poet [entries|archive|friends|userinfo]
Jen's Sweetie and Code Poet

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Google, Firefox, and Privacy [Dec. 11th, 2007|05:42 pm]
Jen's Sweetie and Code Poet
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[Hey, I'm on a roll.]
[Edit: forgot step #5]

While I'm ranting about potential privacy issues, I thought I'd point out something annoying that happens when Google and Firefox get together.

At some point, someone convinced some of the Firefox developers to add a 'prefetch' feature to speed up web browsing. This means that it will automatically download some of the links in the background, making your browsing experience appear to be a bit faster.

Google makes use of this feature -- they mark the first few links (the ones you are most likely to click on) with a marker that says 'prefetch these links'. Thus, while you are pondering what result is actually useful, it can actually load them.

Sounds good right? The uncomfortable part comes along when you have a site like Amazon.
  1. You do a search for something and Amazon ends up in the top-5. Amazon has a huge Page Rank and has a ton of content, so this isn't especially unlikely. Even if you aren't looking for a product.
  2. Pre-fetching kicks in. A request is sent for some product page.
  3. As a side-effect, Firefox will send your Amazon cookie (if you've previously logged in).
  4. It will also send the contents of your query (because it is embedded in the Referrer header).
  5. Amazon now associates it with your account as a 'visit' (for recommendations, history, etc)
The first time I noticed this, I visited Amazon after a doing a few Google searches and noticed that it had recommendations for me that were "similar to one of my recent searches". I thought I was losing my mind for a while ;)

How to turn this feature off:

You can read more about link prefetching (pretty technical) at the Link Prefetching FAQ. They also explain how to disable it. 

Unfortunately, this isn't exposed via the UI (you need to play around with about:config).


[User Picture]From: fianna
2007-12-12 03:40 am (UTC)
I TOTALLY noticed this with Amazon recently. My recommendations that it was giving me were not things I had actually searched for on there and I was really confused D:
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