Back in April, Facebook unveiled App Links, its effort to enable mobile apps to deep link to one another, effectively making the mobile app ecosystem more like the world wide web that we’ve all come to know and love. Your app could, for example, link to specific Wikipedia articles or IMDb pages within those actual apps rather than just web versions, making the user experience more fluid (at least for those with said apps installed on their devices).

Will you adopt App Links in your own apps? Let us know in the comments.

It looks like App Links are gaining some early traction. Facebook announced last week that over a billion unique app links had already been enabled. Let’s hope things in this new linked app web are running more smoothly than app links were in their earliest days. Otherwise, things are going to start looking annoyingly broken for smartphone users.

Facebook says hundreds of apps have already adopted App Links. These include Spotify, Mailbox, Quip, Hulu, Redfin, Goodreads, Live Nation, and Vimeo. SDKs like the Xamarin SDK and the Facebook.NET SDK are also using App Links.

“With App Links, you can drive people into your app directly from stories on Facebook, whether they’re published from your app, from a Page, or from people copying and pasting URLs,” says Facebook’s Gokhan Caglar.

Facebook also made App Links available in mobile app ads through its Preferred Marketing Developer program.

“When you are on your phone and click on a Redfin link, App Links takes you to the Redfin app for a more seamless home shopping experience,” explains Sasha Aickin, CTO of Redfin. “This is obviously great for our customers and it solves a frustrating development problem that my team — and every other mobile developer — has faced over the years.”

“Perhaps the best part about App Links is how easy it is to integrate,” says Caglar. “Simply copy and paste a few tags into your website header to get started. If you have a mobile-only app, you can publish tags directly using the App Links Hosting API.”

Why did Facebook feel the need to launch App Links when so many apps are already Facebook connected?

When it first announced the endeavor, the company said, “Right now, linking on mobile is a lot more frustrating and complicated than it is on the web,” Facebook explains. “There isn’t an easy, consistent way to control what happens when someone clicks on your content in mobile, which makes it difficult to provide the best experience for your users. It’s also hard to find out when—and how—to send people out of your app and directly into another. We built App Links to help with that.”

It actually sounds pretty good in theory, as long as it works. Just after developers gained access, flaws were discovered.

Kevin Marks, who was VP of Web Services at BT, Principal Engineer at Technorati, has held positions at Apple, the BBC, and Salesforce, and is one of the founders of Microformats, shared a couple videos on YouTube criticizing App Links while demonstrating some issues. They’re titled “Facebook App Links Break the Web”.

“What they’re doing is getting in between links on the web,” said Marks in one of the videos. “For example, if I click on this link inside the Facebook app on my phone, instead of going to Medium, where it’s linking to, it actually takes me to the app store, and tells me to download Twitter, which is already downloaded. I’m not sure how this is going wrong, but it does illustrate why letting Facebook resolve links instead of web mechanisms is potentially a bad idea.”

He said, “Using Facebook App Links on iOS, if I click on a link to Medium with Medium installed, it takes me to an embedded webpage via t.co because it was sent from Twitter, and it shows me the Medium page, and it works, but at the bottom, it says, ‘Open in the Twitter app,’ which is kind of weird. If I click ‘open,’ it opens Medium, which I have to sign into with Twitter…so I’m not sure that was better than clicking on the link to be honest. I’m not sure why Facebook thinks Medium is Twitter, but it’s clearly a problem.”

This was at the beginning though, and while there are no doubt bugs to be worked out, we haven’t really seen much else in the way of these kinds of complaints. These videos do, however, show the potential for “web breaking” issues.

Chris Messina, a trusted voice in open standards and an open web advocate had some decent early words for Facebook’s initiative:

AppLinks seems like a not-terrible idea. Though it’s kind of a bummer that the app-web has brought this kind of fragmentation to the document-web.

Here’s an f8 session in which Facebook engineering manager Jason Clark and product manager Vijay Shankar discuss making your apps linkable and link to other apps to improve user experience, engagement, and advertising:

You can find the documentation here.

Do you see any negatives with App Links? Will you use the standard? Let us know in the comments.