Your email signature can be used to communicate tons of good (and important) stuff. Make sure your name, contact information, phone, fax, email, URL and everything is in there. Make it easy to download into an address book so that people don’t have to go hunting for it. Also include any special credentials, awards, or offers you are currently running or reminders of upcoming events. Include links to landing pages or interesting content on your site.
It’s easy to implement and edit, and you’ve got another channel to remind people about important information.