When Twitter upgraded their mobile application this year, to a version called “New, New Twitter”, there was one significant change.  When I clicked on a link, rather than open my Chrome browser to load the web page, Twitter loaded a built-in browser.  This made a seamless transition between Twitter and the web, without ever leaving the app.

In the past few weeks Facebook updated their mobile app as well.  And guess what?  It now does the exact same thing as Twitter.  That means Facebook has a browser too.

So what is all the fuss about web browsers?

Back in 2010, Time Magazine wrote that browser technology was an altruistic pursuit.  If a user stayed on all Microsoft products – Windows OS, Internet Explorer, and Bing – the web would somehow work better for the consumer.

That is just nonsense.

The truth is that the browser captures data, which has become an important asset in the digital age.  Information about what websites people visit, commonly called “behavioral data”, provides the core insight to make online advertising work.  Owning a consumer’s web browser is the best way to see all of this behavior. (And, in case you were wondering, even the privacy advocates at Firefox get all their money from Google.)

Now that Facebook and Twitter come with mobile web browsers, their users are completely invisible to Google.  There is no Google Chrome activity and, most importantly, no search revenue.  It is a black hole.  And you can multiply that across a billion users.

This should get your attention.  “Facebook Browser” market share is not being measured by any official sources, but the company has so many page views that their mobile browser is likely #3 in the world right now.  The only mobile browsers with a larger footprint are Android and Safari because they are bundled with  your phone.

In addition to the data, another benefit of owning the browser is that you can determine what happens when a consumer mis-types a URL.  In the case of Google, if you type Nike into the browser (without the .com) they take you to a page filled with pay-per-click Nike ads.  If Facebook had a working search engine they could profit from this as well.

As a start-up investor, I think Facebook and Twitter’s new browser is good news.  Google has become dominant in too many categories for my comfort.  I don’t even know all the ways that Google is making money, but whenever I browse the web I know the meter is running.

When I look across the tech landscape there are very few companies that can mount an attack on Google. In this new iteration, Facebook and Twitter are using their mobile products to keep traffic for themselves. This is reminiscent of the walled garden strategy used by Prodigy, Compuserve, and AOL in the early 1990s.  And who knows, maybe this time around it will even work…