Sent from my superior device

First there was:

Sent from my Blackberry

The purpose was to let people know that they should forgive the brevity and the typos, and that the author had a fashionable device.  It was soon to be beaten:

Sent from my iPhone

To avoid being seen as trying to be fashionable, a more neutral signature was invented:

Sent from my mobile device

Financial analysts and product managers could advertise their iPhones, but the real nerds had a device that was not even available yet in stores:

Sent from my G1

Even realer nerds needed to point out that Android is not limited to any device:

Sent from my Android capable device

But that seemed a bit too long:

Sent from my droid

In order to make sure readers knew why messages were so long and perfect, quite a few people invented:

Sent from my computer

Really old nerds with beards sign:

Sent from my iBM

Salu2