And while Twitter is no place for grammatical purists, it’s hard to resist parsing what must have been a carefully crafted début. With the addition of a comma—“Welcome to the world, Caitlyn”—Jenner’s tweet includes a salutation to herself—a hopeful prefiguring of the warmth with which her announcement so gratifyingly has been embraced. Without the comma, though, the sentence is an imperative to the reader—more forceful, less eager to please. Caitlyn is here; she is to be welcomed; get used to it. Those two meanings demarcate the space in which Jenner now lives, also captured by Leibovitz’s remarkable portrait: between the vulnerable desire to be accepted as she is and the steely repudiation of those who would deny the justice of that longing.
Rebecca Mead, in Caitlyn Jenner’s Big Début – The New Yorker.