Time is more precious than money. Money is a renewable resource. Everyone always has the potential to make more money. Time, on the other hand, is finite. There are only so many hours in a day. By definition, you only have so much time to give.

The finite nature of time means that, in the world of the attention web, the competitive landscape is all encompassing. Everything is in competition with everything else. Facebook is as much in competition with Twitter, as it is with Spotify and Apple Music, Gawker and BuzzFeed, Hulu and YouTube, Candy Crush and Two Dots, Amazon and Walmart, Xbox and Playstation, Chipotle and your family dinner table, your hobbies and your bed. Because in the attention web, time spent shopping, eating, talking, playing, or sleeping is time that you are not looking at ads. It’s why Facebook has experimented with in-feed shopping. It’s why they bought a messaging app and VR company. It’s behind their big drive into video, as well as article self-publishing. They have to compete on all fronts to win the attention war. If they could serve up your meals they would.

Coca-cola talks about trying to win “share of stomach”, acknowledging that they are not just in competition with the other players in the drink industry, but in competition with every other food company and restaurant for the finite resource of stomach real estate. The attention web has taken this concept to a new scale that pits a vast array of industries against each other. This broad, unending competition for people’s time takes its toll on even the most popular services. See Twitter, Yahoo, Zynga and others.

As with all finite resources, there is a physical cap to how much time can be mined from the world, with population size as the forcing function. The number of people on the internet is directly proportional to the amount of time available. If you assume that technology companies want to maintain their growth curves, there are three possible avenues for them to take against this constraint:

Grow the size of the population with internet access.

Free up more time for the people who already have internet access.

Or create more people.

While no tech company is currently trying to create more people (except maybe Tinder) the other two paths have already started to manifest. Major players are trying to expand global internet access. Facebook’s internet.org initiative is geared toward bringing free internet access to populations without it, and Google’s Project Loon is designed to create a balloon-based network delivering reliable internet to isolated rural areas.

Google is also one of the best examples of a company taking the second avenue: free up more time for people who already have internet. Their push into self driving car technology has a lot of potential benefits for humanity, but it also does something fundamental for Google and their business model. Time spent in the car is a vast untapped reserve of human attention. If your daily commute isn’t filled with trivial things like watching the road and trying not to kill people you suddenly have a lot more time to search — and be served search ads. Building a self driving car may seem like extreme measures just to free up people’s time, but it’s really just the tech equivalent of fracking — Oil’s extreme attempt to unlock untapped reserves.

At some point though, the reserves run out, and as more and more competitors (from almost every industry) come onto the scene, all vying for their slice of the time pie, simply expanding internet access and freeing up time isn’t enough. You still have to win people’s attention.