This kind of communication has been technologically possible for decades now, but for much of my lifetime it had to occur in fixed locations (in front of computers) at fixed times (when you were all online; this was back when the idea of being “online” or “offline” still had meaning). Then smartphones smashed that distinction. In 2008, Apple made it possible to text-message multiple people at the same time, moving limited SMS messaging into their iMessage system — essentially conflating “texting” and “messaging,” collapsing group conversation into a single organized chain. Cell carriers and competitors followed, and slowly, over the next decade, the group chat moved from an occasionally convenient tool — say, something your sister might use to blast big news to a large family group — to a ubiquitous social phenomenon.

My own group chats serve a wide range of purposes, from the purely practical to the highly intimate. There is a taxonomy — not quite a hierarchy, but not not a hierarchy. Some are basically purpose-driven and never meant to last: A new chat might pop up for a wedding weekend, a set of unsaved numbers asking one another questions about the location of a brunch, a fleeting collective of friends-of-friends that loses touch on Sunday night. Some are more or less affinity groups: I am in two separate chats for Grateful Dead enthusiasts, both of which tend to move at the pace of old-school internet forums. (Someone posts a good live version of “Scarlet Begonias,” or a joke about Bob Weir, and we all give it a thumbs-up or a heart or a “ha ha” reaction, iMessage innovations that make even-more-passive communication possible.) Some group chats map almost exactly onto I.R.L. groups of friends and are used for a combination of idle chatter and social planning; one has become such a dominant feature of my social life that it is simply named “The Girls,” as if there were no other girls. (The act of naming of a group chat in iMessage indicates, to some degree, its staying power, no matter how silly the name itself may be.) Thus “The Girls” has become one of the first places any of us would look to make social plans. At least, I think so — it is highly possible that for one or another of us there is another group chat, totally unknown to me, that is more important.