A gem of a little program, which allows someone to type in a code or abbreviation and have it expand into any text desired.  An example of how I use it in PhpLanguage:

* .1. expands to mysql_query(
* .2. expands to or die(mysql_error());

An example of how I use it with support email:

* .sig. expands to my signature
* .blowoff. expands to:

Hi %PROMPT:Name%,

Thank you for taking the time to express your opinion. We are always looking for ways to improve our service, and I assure you that we will give your suggestion its due consideration.

Please note that the .blowoff. text is only for the most obnoxious and condescending of emails that we receive.

Do other programmers use it?  It's been a productivity boon for me in a lot of ways.