For years now, the way contact sharing has worked on iOS devices is that an app can trigger a message called a “data access prompt,” asking for access to a user’s contacts.

If the user agreed, the app developer got a list of all the contacts in that user’s address book, along with other information stored in the user’s contact cards, such as phone numbers and email addresses. App developers could then use that information to build out a user’s social graph, or suggest other accounts for the user to follow.

In iOS 18, however, users who agree to give an app access to their contacts are shown a second message, allowing them to select which contacts to share. Users can opt to share just a handful of contacts by selecting them one by one, rather than forking over their entire address book.

Apple’s stated rationale for these changes is simple: Users shouldn’t be forced to make an all-or-nothing choice. Many users have hundreds or thousands of contacts on their iPhones, including some they’d rather not share. (A therapist, an ex, a random person they met in a bar in 2013.) iOS has allowed users to give apps selective access to their photos for years; shouldn’t the same principle apply to their contacts?

Apple also made it clear that it didn’t think the iOS 18 changes would hurt app developers. In fact, the company told me, developers might see an uptick in contact sharing, if users who previously would have declined to share any contacts can just share the ones they want.

App developers think that’s a bogus argument. Bier told me that data he had seen from startups he advised suggested that contact sharing had dropped significantly since the iOS 18 changes went into effect, and that for some apps, the number of users sharing 10 or fewer contacts had increased as much as 25 per cent. (Other developers said their own apps had experienced similar declines, though nobody except Bier would agree to speak on the record, out of fear of angering the Cupertino colossus.)

A 25 per cent decline in contact sharing might not sound like a huge change. But for social apps, the ability to quickly connect new users with their friends can mean the difference between success and failure. Facebook, for example, discovered during its early days that if users added seven friends within 10 days of signing up for an account, they were more likely to stick around than users who didn’t.

“It’s critical to form density on an early-stage app,” Bier said. “People don’t wait around for a week for all their friends to sign up.”

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Some developers also pointed out that the iOS 18 changes don’t apply to Apple’s own services. For example, iMessage doesn’t have to ask for permission for access to users’ contacts the way WhatsApp, Signal, WeChat and other third-party messaging apps do. They see that as fundamentally anticompetitive — a clear-cut example of the kind of self-preferencing that antitrust regulators have objected to in other contexts.

Of course, iPhone users can still upload their whole address books if they choose. (There’s also Android, which still requires users to make an all-or-nothing choice.) But it’s reasonable to assume that the added friction of a second screen will result in fewer contacts being shared.

The result, Bier said, might be that friend-based social apps will simply be replaced by apps like TikTok, which show users content based on what they like rather than whom they’re connected to, or AI companionship apps that don’t require humans at all.

“You’d have to be pretty crazy already to do a friend-based social app,” he said. “Now, it’s all but impossible.”

This article originally appeared in The New York Times.

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