[biturd]

I agree. I change it to say "Sent from a mobile device". There are cases where a message mandates a reply but a mobile device isn't to an ideal platform. iPhone only recently allowed file attachments beyond 1, and that was if you remembered to attach it first. I don't think you could even attach to replies.

Many emails do necessitate a reply but you aren't going to be able to spellcheck and put the time into it as you would on a desktop. Afterall, you are mobile.

Stating so in the signature lets the recipient know you are giving them your full attention as much as the technology and situation will allow. I've always felt it was a good thing when users noted this.

And of course, as someone has mentioned, it is the default on iOS devices. Then again, users unable to edit their default signature probably aren't giving you their full attention and the reply will amount to yes/no or worse, not answer a single question with any sort of detail. Not that if the user were on a desktop that would change a bit. I'm not sure how these people are employed as I would fire so many people over the way they handle email.