Huh. I always thought the point of "Sent from my iPhone" (or the earlier "Sent from my Blackberry") was that it indicated "I don't have access to my desktop and file server right now so don't expect me to send that file".

That's one way that it works, but that's not the main driver.

This kind of tagline marketing works best with people people who aren't even aware that they're participating, and who aren't bothered to do anything different it even if they become aware.

The juice isn't worth the squeeze, so the marketing remains.

  Sent from my iPhone
  Downloaded from Demonoid
  Rusty n Edie's: The world's friendliest BBS 216-726-0737

However, there's one counterexample: some email clients in the past experienced explosive growth by adding signatures. It was annoying, but it definitely worked.

Microsoft already does this with their mobile Outlook. Sent by Outlook Android / iOS on the bottom of the message.

I don't really send emails anymore but when I actually used email to keep in touch with friends (during the interesting bit of time between smart phones becoming mainstream and SMS and other messaging services becoming more popular than email), I changed my signature to be "Sent from your iPhone" even though I used an android and mainly sent emails from my computer, just to be an edgy teenager. Got some interesting responses from that.

It's interesting to see how communication, digital and otherwise, has evolved over time.

But you can see it and remove it before sending. It’s definitely not the same.

Does anybody else remember Tapatalk? They did the same with signatures in forums.

"sent from my iphone" originally meant more than just "i have a fancy phone that lets me send email" in the early days it meant "I'm not at my desk right now."