Navigating the Internet used to mean painstakingly typing the exact address you wanted into your computer. The Web browser and the search engine simplified that, giving us the Internet we take for granted today. Now, across Silicon Valley, companies from tiny startups to titans like Google and Facebook are trying to bring the same simplicity to smartphones by teaching apps to talk to one another.

Unlike Web pages, mobile apps do not have links. They do not have Web addresses. They live in worlds by themselves, largely cut off from one another and the broader Internet. And so it is much harder to share the information found on them. It is not just a matter of consumer convenience. For Google and Facebook, and any company that has built its business on the Web, it is a matter of controlling the next entryway to the Internet – the mobile device.

“Google’s whole concept is we’re going to index the world’s information, but they’ve left out a whole lot of stuff: all the things that are inside apps,” said Alex Austin, chief executive of Branch Metrics, a startup in Palo Alto, California, that is trying to create a universal Web address that would work across apps as well as the Web.

Say you want a hotel for a weekend stay. You could Google for deals or go to a travel site. But wherever you go on the Web, you will not find the rooms on HotelTonight, an app that offers steep discounts for last-minute bookings. The only way to get those listings is to use the app. And if you find a few hotels on HotelTonight, you cannot email them to your spouse, because there are no links to send. That is but one example involving one app. But as people spend more time on their mobile devices and in their apps, their Internet has taken a step backward, becoming more isolated, more disorganised and ultimately harder to use – more like the Web before search engines.

“How remarkable it is that we are back in 1997!” said Roger McNamee, co-founder of Elevation Partners, a technology investment firm in Menlo Park, California.In tech speak, the problem is known as “deep linking,” the technological hurdle of giving apps some sort of links – those identifying lines of letters, dots and slashes that make up a Web address or URL.

Although deep linking is a worry for large tech companies, it is also a big opportunity for startups looking to unseat them. As Austin put it, “Whoever gets the best database will win this game.” His Branch Metrics and other startups in the field, including URX and Quixey, are trying to become app developers’ go-to technology for deep linking. The efforts vary in scope, and the companies have wildly different business models.

Some people say it is like outfitting a house with plumbing after the house has been built. “It’s the exact same problem that Google was chartered to solve,” said John Milinovich, chief executive of URX.

For the Web’s well-known giants, deep linking is a way to protect their businesses by creating mobile versions of things they do on the Web. Take Google, which makes money helping people search the Web. When people search in apps, it is mostly left out. And while the company has a fast-growing business selling apps through devices that use its Android operating system, that pales in comparison to its business selling search advertising.

Google’s solution is App Indexing technology, a way to catalogue app pages, letting Google’s search engine retrieve information from mobile applications as well as from Web pages. Twitter has Twitter Cards, which makes it possible to go from the Twitter app to another app in the user’s phone, rather than from the Twitter app to the Web. If the user does not have the app he or she wants to see installed on a phone, Twitter will ask if the user wants to install it immediately.

Facebook is trying to create an open standard of deep links to help apps connect to one another, so that, for instance, someone could go from listening to a band in the Spotify app to finding information about the band’s live appearances in Songkick, another app.

With so many companies and investors working on deep linking, the competition itself has become a problem. That is because the easiest way to get apps to link together as if they were part of the Web is to get app developers to adopt a single standard that would work across devices and operating systems.

“Once we’re all using the same plumbing, everyone can go and build businesses and interesting experiences on top of that,” said Eddie O’Neil, a Facebook product manager working on the company’s programme.

The app problem began in 2008, when Apple introduced the App Store for iPhones. Unlike websites, apps were set up to be separate little boxes whose technology prohibited them from interacting with one another. 

At the time, the idea of a phone full of apps was new enough that most people were not very worried about whether those apps could link to each other. But today, apps have basically usurped the Web. Americans spend about half of their time online using mobile apps, according to comScore.Repackaging websites like apps

If apps are so much trouble, why use them at all? This is the idea behind another kind of startup: those trying to turn the link problem on its head by making websites work more like apps. Famo.us is a San Francisco company that develops software to repackage websites in such a way that they can be sold and downloaded like apps, but still can be searched and linked like Web pages. Steve Newcomb, the company’s chief executive, described efforts to add links to apps as
“duct-tapey” solutions that are more trouble than they are worth.

Some app makers may resist any of these solutions – especially if they are doing brisk business in apps. It would be hard to index something as complex as HotelTonight’s rolling hotel inventory, for example, without having those services give some search engine a continuously updated feed of their data, something they would not want to do.

“The most successful apps are successful because they’re doing something you couldn’t do on the Web,” said Sam Shank chief executive of HotelTonight. “All of our info is in real time; it can go stale pretty quickly.” But even if the technology were an easy fix, there are plenty of other reasons to keep apps walled off. “Hotels really like that we don’t compete with their websites,” he said.

Still, whether it is deep-linking or something else, the mobile world will eventually become interconnected, said Sam Altman, president of Y Combinator, a technology incubator that invests in young companies.

“The thing that made the Web so magical was that there is no friction to move from one place to another,” he said. “You could move from a song to buying tickets to getting directions. It was this deep interconnectivity of everything.” He added, “People will lose a bit of their stronghold, but it will be unstoppable.”