# How does Twitter know about my browsing history? **URL:** \ **Category:** Factual Questions\ **Created:** [May 18, 2015, 6:54am UTC](https://boards.straightdope.com/t/how-does-twitter-know-about-my-browsing-history/720294 "2015-05-18T06:54:37Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Donnerwetter](https://avatars.discourse-cdn.com/v4/letter/d/b2d939/32.png) [@Donnerwetter](https://boards.straightdope.com/u/Donnerwetter)\ **Post date:** [May 18, 2015, 6:54am UTC](https://boards.straightdope.com/t/how-does-twitter-know-about-my-browsing-history/720294/1 "2015-05-18T06:54:37Z")
Twitter regularly sends out “Popular in your network” emails. I’m assuming one of the reasons is to encourage some of the less active users (like me) to be more active on this social network. Today, Twitter informed me that this Tweet is “popular in my network” > [@](#): > > Nova Scotia Museum > @NS\_Museum > > Join us June 6 for the opening of the Black Loyalist Heritage Centre #JourneyBackToBirchtown blackloyalist.novascotia.ca What’s surprising about this is that I live an ocean away from Canada and that I don’t follow any Twitter users from Canada and definitely not from that part of the country. However, and this is the interesting part, I recently (on the weekend) did do a Google search on Labrador which sent me to this Wikipedia article: > **[Labrador](https://en.wikipedia.org/wiki/Labrador)** > > Labrador (/ˈlæbrədɔːr/ LAB-rə-dor) is a geographic and cultural region within the Canadian province of Newfoundland and Labrador. It is the primarily continental portion of the province and constitutes 71% of the province's area but is home to only 6% of its population. It is separated from the island of Newfoundland by the Strait of Belle Isle. It is the largest and northernmost geographical region in the four Atlantic provinces. > Labrador occupies most of the eastern part of the Labrador Penin... I also recall then clicking on a link which led me to the article about Nova Scotia: > **[Nova Scotia](https://en.wikipedia.org/wiki/Nova_Scotia)** > > Recognized Regional Languages: > Nova Scotia (/ˌnoʊvə ˈskoʊʃə/ NOH-və SKOH-shə; French: Nouvelle-Écosse; Scottish Gaelic: Alba Nuadh, lit. 'New Scotland') is a province of Canada, located on its east coast. It is one of the three Maritime provinces. > Nova Scotia is the most populous province in Atlantic Canada, with an estimated population of over 1 million as of 2024; it is also the second-most densely populated province in Canada, and second-smallest province by area. The province comprises t... From there, I proceeded to the article about Black Loyalists: > **[Black Loyalist](https://en.wikipedia.org/wiki/Black_Loyalist)** > > Black Loyalists were people of African descent who sided with Loyalists during the American Revolutionary War. In particular, the term referred to men enslaved by Patriots who served on the Loyalist side because of the Crown's guarantee of freedom. > Some 3,000 Black Loyalists were evacuated from New York to Nova Scotia; they were individually listed in the Book of Negroes as the British gave them certificates of freedom and arranged for their transportation. The Crown gave them land grants and su... It is important to point out that I usually surf the web using Google Chrome’s “[incognito mode](https://support.google.com/chrome/answer/95464?source=gsearch)”, which was also the case with regards to the aforementioned search history. I’m also permanently logged in into Twitter and into Google, but only in my **other** , regular Chrome window. If the “incognito mode” works as advertised, neither Twitter, nor Google should have had a record about me looking up Nova Scotia and/or Black Loyalist. BTW, something similar happened a couple of weeks ago when I looked up “Long Beach” (in California): The next day Twitter pointed me to a Tweet by an organisation based in Long Beach. How does Twitter know about all this? ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [May 18, 2015, 7:18am UTC](https://boards.straightdope.com/t/how-does-twitter-know-about-my-browsing-history/720294/2 "2015-05-18T07:18:21Z")
I’m not sure you understand the Incognito Mode. Check out its own disclaimer next time you turn it on: > [@](#): > > Pages you view in incognito tabs won’t stick around in your browser’s history, cookie store, or search history after you’ve closed all of your incognito tabs. Any files you download or bookmarks you create will be kept. Learn more about incognito browsing > **Going incognito doesn’t hide your browsing from your employer, your internet service provider, or the websites you visit.** (Bolding not just mine; it’s bold in the Chrome window as well.) So Incognito mode is only limiting Twitter’s tracking by trashing the cookies at the end of your session. Thus, they’re not there next time. However, within the same session (as long as any tab/window is open), they can potentially track you. ---
**Author:** ![Donnerwetter](https://avatars.discourse-cdn.com/v4/letter/d/b2d939/32.png) [@Donnerwetter](https://boards.straightdope.com/u/Donnerwetter)\ **Post date:** [May 18, 2015, 7:37am UTC](https://boards.straightdope.com/t/how-does-twitter-know-about-my-browsing-history/720294/3 "2015-05-18T07:37:54Z")
I think I do understand the incognito mode. Again, I have two Google chrome browser windows (not tabs) open at any given time: #1: a regular browser window where I am logged in into all the online services I use (Twitter, Facebook, Google, Amazon and also this discussion board); it is perfectly understood that my browsing history is recorded and all my passwords, credentials etc. are permanently stored and accessible #2: an incognito window which I close after every 20 or 30 minutes (something like that) to open a new one. When I look up a Twitter timeline on #2, it prompts me to login with my credentials or to sign up which makes perfect sense. My question is: How does #1 know about what is going on in #2 which is supposed to be incognito and separate? It is also perfectly understood that my ISP knows about my browsing history. ---
**Author:** ![Donnerwetter](https://avatars.discourse-cdn.com/v4/letter/d/b2d939/32.png) [@Donnerwetter](https://boards.straightdope.com/u/Donnerwetter)\ **Post date:** [May 18, 2015, 7:50am UTC](https://boards.straightdope.com/t/how-does-twitter-know-about-my-browsing-history/720294/4 "2015-05-18T07:50:35Z")
And I might add: Even if I didn’t use an incognito window for my regular browsing, but my regular window which records my browsing history, accepts all the cookies and which I use to permanently access Twitter and Google: I still would find it dubious that Twitter should have access to this information. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [May 18, 2015, 11:26am UTC](https://boards.straightdope.com/t/how-does-twitter-know-about-my-browsing-history/720294/5 "2015-05-18T11:26:08Z")
Were you dealing with any website other than Wikipedia, I’d expect them to have some twitter-follower software running on their server. That software would be recording that you had been shown pages X, Y, and Z and would be forwarding that info to twitter for their use. So your browser settings would have no effect on this behavior. But that doesn’t explain the behavior at wiki, which is famous for not participating in all that marketing crap. I \*suspect \* what’s really happening is this: Under incognito mode, a local record of history, cookies, etc. is kept as long as the incognito window is open. And if meanwhile you do a pageview in the non-incognito window which includes twitter’s tracking-ware, the incognito history is forwarded along. IOW, incognito mode is about erasing your tracks when the tab/window is closed, not about not creating any tracks in the first place. This avoids all sorts of compatibility problems where sites expect history and cookies and such to be available from page view to page view while actively using that site. I would try a similar experiment with some unlikely wiki pages but without any non-incognito Chrome window(s)/tab(s) running at all. From no browsers open, start your incognito browser session, do your spelunking through wiki, close that browser, then open your normal non-incognito browser and go about your normal activities. I bet you won’t later be surprised by twitter’s knowledge of your incognito history. ---
**Author:** ![Donnerwetter](https://avatars.discourse-cdn.com/v4/letter/d/b2d939/32.png) [@Donnerwetter](https://boards.straightdope.com/u/Donnerwetter)\ **Post date:** [May 18, 2015, 12:53pm UTC](https://boards.straightdope.com/t/how-does-twitter-know-about-my-browsing-history/720294/6 "2015-05-18T12:53:16Z")
> [@LSLGuy](#): > > I would try a similar experiment with some unlikely wiki pages but without any non-incognito Chrome window(s)/tab(s) running at all. From no browsers open, start your incognito browser session, do your spelunking through wiki, close that browser, then open your normal non-incognito browser and go about your normal activities. I bet you won’t later be surprised by twitter’s knowledge of your incognito history. I will try this. IMHO, if the separation between “normal window” and “incognito window” in Google Chrome isn’t complete (like in a sandbox), then this functionality is broken. ---
**Author:** ![Turble](https://avatars.discourse-cdn.com/v4/letter/t/8dc957/32.png) [@Turble](https://boards.straightdope.com/u/Turble)\ **Post date:** [May 18, 2015, 2:46pm UTC](https://boards.straightdope.com/t/how-does-twitter-know-about-my-browsing-history/720294/7 "2015-05-18T14:46:37Z")
Installing [Ghostery](https://www.ghostery.com/en/home) will stop that tracking. You can whitelist the sites you want to allow to track you. ---
**Author:** ![Heracles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heracles/32/487_2.png) [@Heracles](https://boards.straightdope.com/u/Heracles)\ **Post date:** [May 18, 2015, 3:01pm UTC](https://boards.straightdope.com/t/how-does-twitter-know-about-my-browsing-history/720294/8 "2015-05-18T15:01:45Z")
I’ve used Chrome’s Incognito mode this way for years and have never seen this sort of leak. I hope they haven’t broken it. Three possibilities I see: - Tracking services are getting wiser and identifying you based on your IP address, possibly mixed with your browser’s UserAgent info and whatever demographics they can deduce based on your behaviour. - There’s a Chrome add-in that’s found a way to cross the barrier between regular and Incognito. - There’s a secondary device involved (smartphone, tablet) and it associates the Google identity you use in Incognito with your regular Twitter account. ---
**Author:** ![Mithras](https://avatars.discourse-cdn.com/v4/letter/m/f04885/32.png) [@Mithras](https://boards.straightdope.com/u/Mithras)\ **Post date:** [May 18, 2015, 4:01pm UTC](https://boards.straightdope.com/t/how-does-twitter-know-about-my-browsing-history/720294/9 "2015-05-18T16:01:15Z")
> [@Heracles](#): > > I’ve used Chrome’s Incognito mode this way for years and have never seen this sort of leak. I hope they haven’t broken it. > > Three possibilities I see: > > - Tracking services are getting wiser and identifying you based on your IP address, possibly mixed with your browser’s UserAgent info and whatever demographics they can deduce based on your behaviour. > - There’s a Chrome add-in that’s found a way to cross the barrier between regular and Incognito. > - There’s a secondary device involved (smartphone, tablet) and it associates the Google identity you use in Incognito with your regular Twitter account. I don’t think incognito mode creates much of a barrier for an extension to cross. If you have an extension installed and enabled for incognito mode, it can send your browsing history wherever it wants. **Donnerwetter** , do you have any extensions running in incognito mode? ---
**Author:** ![Donnerwetter](https://avatars.discourse-cdn.com/v4/letter/d/b2d939/32.png) [@Donnerwetter](https://boards.straightdope.com/u/Donnerwetter)\ **Post date:** [May 18, 2015, 6:35pm UTC](https://boards.straightdope.com/t/how-does-twitter-know-about-my-browsing-history/720294/10 "2015-05-18T18:35:01Z")
> [@Mithras](#): > > I don’t think incognito mode creates much of a barrier for an extension to cross. If you have an extension installed and enabled for incognito mode, it can send your browsing history wherever it wants. > > **Donnerwetter** , do you have any extensions running in incognito mode? As far as I can see: no. I am also under the impression that extensions don’t run in incognito mode by default (but I could be totally wrong about this).