Lara Williams, writing for The Guardian:

Is there a more divisive valediction than the default “Sent From My iPhone” sign-off? When the iPhone first appeared, users were roundly condemned for their thinly veiled humblebrag among the mounting popularity of Apple products.

The message was clear: having an iPhone was so much more than having something on which you could make calls and browse the internet. It was a gorgeous trinket and elite lifestyle marker that signalled both sophistication and technological know-how. Membership of the club was something to be boasted about, and you could feel the conceit as users pressed send. The backlash was immediate.

And:

Recently, however, the refrain has returned to our correspondence, but those using the sign-off can no longer be accused of not knowing how to switch it off (it’s easy) or gloating (it’s not a big deal). Rather the phrase has become an important part of online decorum. Including the sign off contains an innate apology for the brevity of the message. It begs forgiveness for any spelling or grammatical errors. It allows a little wiggle rooms for errant emojis. It is a nod of acknowledgement that you are on the hoof and doing as well as can be expected.

Nice writeup, solid read. Not to mention the genius of whoever thought to include that feature in the first place. My money is on Steve.