How many emails do you send each day? And how many of them get forwarded to other parties? Probably too many to count.

Email has become one of our most frequently used communication tools, but there's more to it than meets the eye--email is an opportunity to market your brand. There is an overlooked, underestimated opportunity in every single email you send: the signature line. This valuable piece of real estate can inform, engage, and increase brand awareness. When was the last time you paid it the attention it deserves?

Dust off your signature line and make it useful, rather than invisible, or worse yet, annoying. Here are five ways to put it to work for you.

1. Include cool stuff.

The signature line is a great place to spread the word about your social media presence and any outstanding achievements. Have you won an award, been on television, or been featured on inc.com? Include that information, along with a link! Also, be thorough about the contact information you include. Don't make people search for your phone number when it should be right at their fingertips.

2. Relay your brand's purpose.

Hopefully, your tagline includes your purpose. Sum that purpose up into a few powerful words and include it in your signature area. At the very least, seeing it will embed it subconsciously in the minds of many. Your bigger purpose is something you're proud of--give it a well deserved home on every email.

3. Brand yourself, not someone from the 18th century.

Quotes are nice; they inspire and remind people of what's important. But you are unique; you have your own thoughts and beliefs and are capable of inspiring others in your own words. I personally believe it's more important to use this space to express your brand purpose, but if you must include a quote, make it your own.

4. Remove images, like logos and embedded business cards.

Many email systems turn your signature graphics, like logos and embedded business card images, into attachments. Your signature line will appear stripped down and rendered useless, even annoying, when you use graphics. Instead, use fonts and colors that reflect your logo. Consider that information like your website address and phone number cannot be copied and pasted into calendars or documents when you display them as a graphic. Stick to text for optimum effectiveness.

5. Less is more.

Don't be tempted to include every single means of contacting you. If you're not a brick and mortar retailer, it's unnecessary to include your physical address. Multiple websites and more than two phone numbers overwhelm and clutter the space.