The inspiration comes from an an article from Gartner analyst, Craig Roth, Sent from my iPhone, where he grouses about people who send email with the signature "Sent from my iPhone" or "Sent via Blackberry please excuse any typos" or similar signatures.
There are many aspects to why these signatures exist. People want to excuse themselves from poor typing or brief responses. Or they want to show off that they are using a mobile gadget (probably not any more). I argue that a big reason is that people may not know how to change that signature.
So, in an attempt to help you personalize your responses, here are ways to customize your signature on several major smartphone platforms. You can usually find this information via a search for "email signature" and the name of your smartphone (plus the model for BlackBerry and Android users).
In general, I recommend keeping your signature as simple as possible, whether on your phone or on your regular email client. I use my phone for business and personal, so I keep the signature at a business level: my name, the name of the company, and my phone number.
As with most things iPhone, this is under the Settings application. Click on the "Mail, Contacts, Calendars" entry and then scroll down a bit to the "Signature" entry. This will give you an edit box to make as complicated (or not) a signature as you like.
Note that on the iPhone, there is only one signature possible, no matter how many email accounts you have set up on the phone. I'd prefer to have a different one for every account, so that personal email feels more personal.
Caution: From what I read, there are many ways to do this, depending on the phone model and if you are using a company-managed phone (BES = BlackBerry Enterprise Server), vs the consumer BlackBerry services (BWC = BlackBerry Web Client or BIS = BlackBerry Internet Service). You may need to try all options or do a phone-specific search, if none of these work.
On the phone (if available): In the Mail application, go to Options, then click Email Settings. (You may need to click the menu button to select a specific email account.) Then set the Use Auto Signature field to Yes (or No to turn off completely). Type a signature. Click the trackwheel. Click Save.
BlackBerry Desktop Manager: This is your desktop application, where you should have some ability to modify your email settings. Go into Email settings -> General -> Signature and modify accordingly.
BlackBerry Web Client: If this doesn't work, and you have a non-corporate phone, try setting the signature from the website your provider has set up for your BlackBerry. This is where you should be able to modify your email account settings, add accounts, etc. Once into your BlackBerry page, find the "email management" page and look for "Auto Signature." You can then turn this off completely or set it to something that is more appropriate to your use of the phone. From what I can tell, these are the websites for a number of US and EU-based providers. If your provider isn't mentioned, a search for "BlackBerry Internet Service" and the name of your provider should do the trick.
- 3 (UK): http://3uk.blackberry.com/
- AT&T (USA): https://att.blackberry.com/
- O2 (UK): http://o2email.co.uk/
- Orange (UK): http://www.blackberry.orange.co.uk/
- Sprint (USA): https://bis.na.blackberry.com/html?brand=sprint
- T-Mobile (USA): https://my.t-mobile.com/Login/
- T-Mobile (Germany): http://www.instantemail.t-mobile.de/
- T-Mobile (Austria): http://www.instantemail.t-mobile.at/
- T-Mobile (UK): http://www.instantemail.t-mobile.co.uk/
- Verizon (USA): https://bis.na.blackberry.com/html?brand=vzw
- Virgin Mobile (UK): https://bis.na.blackberry.com/html?brand=virginmobile
- Vodaphone: http://www.mobileemail.vodafone.net/
- Vodaphone (Germany): http://mobileemail.vodafone.de/
Strangely, it seems that only Gmail accounts can have a signature in the default setup on Android (Gmail -> Menu -> Settings -> Signature). In other words, your other email accounts cannot have a signature. That said, given the nature of the Android, there are several applications that allow a signature for each email account you might have. And at least one person has posted a fix by modifying the source code, Email Signature in Android Fixed for Android 2.1 on the Nexus One and the Droid.
Windows Mobile 6
For people on Windows Mobile (6.0, 6.1 and 6.5), this is fairly easy. In the email application, hit the Menu -> Options and then select Signatures. Then select which account you wish to modify the signature. Tick the "Use Signature with this Account" and whether you want to use the signature when Replying and Forwarding. And then create the signature. I found this system to be much more flexible than what I have on the iPhone.
[Photo: (Ernesto Colnago) "Signature Detail" by RobVSF]