By Kevin Roose
This year, when Apple announced iOS 18, the latest version of its mobile operating system, most of the attention went to its slate of new artificial intelligence features.
But a lesser-noticed change in iOS 18 — a tweak to an obscure feature that allows users to share their contact lists with various apps — may wind up being more important.
That’s because “contact sync,” as the feature is known by some developers, has played a critical role in the growth of many social and messaging apps for the past two decades. It’s how apps like Instagram, WhatsApp and Snapchat were …