Ever notice how many email messages you get that end with a note that it was sent from a specific mobile device? When you leave your email signature up to device manufacturers, they'll take full advantage of using your handset to advertise their products. Since you're seeing these messages, their ploy to get some free plugs in is working brilliantly. Unless you want to continue shilling for your device company, we suggest you update the signature on all your services and devices. This is an especially important suggestion for business users - take a minute to change the default signature to help create awareness of your company's website, blog or other marketing-related options. Our assumption as to why so many people still have the default signature in all of their email messages is because they don't know where to go to change it, so here are the instructions! Apple and Android users:and#160; https://www.pcmag.com/news/how-to-change-your-mobile-email-signature Blackberry users:and#160;http://helpblog.blackberry.com/2013/07/blackberry-10-how-to-set-up-an-email-signatureand#160;