Whether you use a stand-alone email program or a website-based email service such as Gmail or Hotmail, you can configure a signature that is attached at the bottom of all email messages you send. This signature is separated from the body of the email by a specific string of characters called the email signature delimiter.
The use of a signature delimiter originated in the original Usenet newsgroups and has since spread to email. The standard signature delimiter consists of a single line of text containing two dashes followed by a space. For example, the email signature for John Smith, CEO of the "Smith and Sons" company, could look like this:
-- John Smith CEO, Smith and Sons
Most email programs and services use the signature delimiter to identify where the body of the email ends and the signature begins, then use the information to visually separate the signature from the rest of the email. For example, GMail displays signatures in a gray color rather than black. Some programs may also offer additional configuration settings, allowing you to change the way the signature is displayed or simply hide it altogether.
Although you can manually edit each email you send to remove the delimiter before your signature, you should avoid doing so. The signature delimiter allows the person who receives your email to identify the body of the message at a glance and only focus on your signature if he finds it necessary; circumventing this feature by removing the delimiter may result in unnecessary frustration and annoyance.
Your email signature should contain only the minimum amount of information necessary to identify you as the sender. Avoid adding too much text to it and keep similar information on the same line, using a pipe character or a double colon to separate it if necessary. For example, the email signature for John Smith, listing his work and home number as well as his company's website and Twitter address, could look like this: