From 2004:

<a href="aim:GoIm?screenname=myscreenname&message=hello">x</a>

mailto: is the same principle and has been around since the 90s.

@satjot - can "they" detect what's installed on your smartphone? If yes, I can see how deep-linking would be a great feature for apps that have high value repeat purchases.

@allantyoung there are a few ways Facebook can compile this data : (1) They could make calls to app url schemes that are publicly known (i.e. http://handleopenurl.com/) to check for a response (2) Facebook will become the largest data set of app url schemes as more apps register their url schema with Facebook when enabling deep-linking (3) Facebook bought Parse, and over 100,000 apps use Parse and many of those apps use FB connect, so Facebook knows which apps those users have

On Android, though, app developers just have to register open intents for their urls, and Android takes care of the rest. No special schemes necessary, and falls back to the browser if the user doesn't have an app installed to handle it. What exactly is wrong with that setup that necessitates a whole new set of schemas that will result in urls that can only be handled if you already have the app installed?

Is there any functional deeplinking comparable to:

    twitter://post?message=hello%world

in the current Facebook app? Lots of older posts indicate fb://publish/?text=helloworld once worked, but it doesn't seem to any longer.

Related standard: http://mobiledeeplinking.org/

Why is this called "deep" linking? What makes it deep?

It is the reinvention of hyperlinking 'deep' into alternate views rather than just the native app's main page. I use it but the reason why it hasn't taken hold is largely because it isn't standardized across platforms.

Here's a routable handler that tries to standardize it: https://github.com/usepropeller/routable-android and https://github.com/usepropeller/routable-ios