"I'll text you" has become one of the most reliable signals of social non-commitment in contemporary American life. It is said at the end of conversations, in the closing moments of chance encounters, when parting from acquaintances at parties and events. It is not a lie exactly — the speaker might well intend to text, in the same way that people intend to exercise and read the books they buy. But it is not a commitment either. It is a social performance of future contact, a linguistic gesture that closes the immediate interaction without the awkwardness of a genuine farewell and without the burden of an actual plan. Both parties typically know this. Both parties typically pretend they do not.
The ubiquity of "I'll text you" — along with its near-equivalents: "we should get together soon," "let's catch up," "I'll reach out," "let's do dinner sometime" — is a collective social phenomenon, not merely a personal habit. It reflects the dominance of low-commitment social signaling in a culture where the performance of social warmth and the maintenance of optionality have both become more valued than the discharge of social obligation. It reflects the substitution of ambient digital connection for the specific, scheduled, mutually committed contact that friendship requires. And it reflects the systematic devaluation of the follow-through that makes social gestures meaningful.
This is not primarily a technology story, though technology participates in it. The "I'll text you" that means nothing predates smartphones; its predecessor was "I'll call you" and before that "I'll write." The form has changed with each communication technology. The substance — the commitment to future contact that is made and not kept — is older. What digital communication has done is lower the friction of making the gesture (it costs nothing to say "I'll text you") while also lowering the social cost of not following through (the absence of a text is less socially conspicuous than the absence of a letter or a phone call). The result is a social environment in which the gesture is cheaper and the follow-through is no more likely, and possibly less.