While philosophers debate the metaphysical and the physics of whether a tree falling in a forest makes a sound when no one is around to hear it, small-business owners are more concerned about the realities of email-marketing programs.

If no one's reading the email campaign, no matter how great it is, it's not going to make any noise for your brand or your sales.

The start of a great email list is one that is filled with customers and prospects who have said yes to receiving information from you and who will be moved to action if the time or offer is right.

But the list needs to grow if you want your business to grow. Asking for an email address at the end of a phone call is a good place to begin, and there are several other ways to add to your list.

Follow these 10 tips, and soon you'll have an email list that helps win business—and is the envy of your competition.

1. Ask for email addresses at the point of sale. If customers purchase from you once, and you do a good job, there's a high likelihood they'll purchase from you again. Tell them they will be notified about discounts on selected items and exclusive email-only specials, and given first notice of sales by signing up for your mailing list, either online or in person.

2. Promote (or start) a loyalty program. A loyalty program makes customers feel special with the promise of exclusive members-only benefits. You can encourage customers to sign up for yours (and give you their email address) with an on-the-spot discount or a special offer, such as a free gift.

3. Offer free information. You may not realize that by sharing a little bit of your business expertise for free, you can entice customers and prospects to give you their email information.

For example, if you're a photographer, you can offer simple tips on how to take better, more interesting photos at family events. If you run a garden shop, you can offer tips on preparing garden beds in the spring and winter, how to care for plants in a draught, etc.

And all anyone needs to do to get that information is give you an email address to send it to. Simple!

4. Conduct a poll or survey. Include a poll about something relevant to your business on your website, or use cards and a box in a store location. As a thank-you for participating, oOffer a free gift or discount that will be sent to each respondent's email address.

5. Hold a contest. Offer a prize (or series of prizes) to anyone who signs up for your mailing list. In a restaurant, set up a fishbowl and collect business cards for a drawing for a free appetizer, meal, or party. An accountant can offer a free consultation; a real estate agent can offer a free home inspection or energy assessment.

6. Use social media to encourage signups. If you already have Twitter followers or a Facebook fan page, ask your followers and fans to sign up for your email alerts. Explain that the emails will include information and offers not available anywhere else. You can make it part of your loyalty program or a separate benefit if you don't have a loyalty program.

7. Hand every customer a postcard. Customers may be squeezing in shopping trips between other activities and may not have time to sign up for an email program on the spot. But if you hand them a prepaid postcard they might fill it out and mail it later. If you also offer them the option of signing up online instead, you'll greatly increase your chances of capturing their email addresses.

8. Capture friends of friends. Every email you send has the potential for a ripple effect—if you encourage the people who are already on your list to pass your emails along to their friends. You can ask people to do it out of the goodness of their hearts, or you can give them an incentive with the offer of a gift or other reward if the friend signs up and mentions them. It definitely helps to offer great content that's worth passing along.

9. Give incentives to your staff. If you have employees, give them reasons to collect email addresses on your behalf. For each name collected, offer a small reward to be given out after the first email is received to make sure the recipient doesn't ask to be taken off the list right away. Or offer a larger cash reward or other prize for the person who provides the most verifiable email addresses at the end of each month.

10. Get out and mingle. Exhibit or be part of local events, such as "Your Town Days," a chili cook-off, or a classic cars weekend. Join the Rotary Club or other organization, and become an active participant.

For B2B owners, attend meetings of special-interest groups or networking events where customers and prospects might be, get their business cards, and ask if it's OK to email information to them.

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Those are just a few ideas to get you started, but there are plenty of others. The key is to do something.

Get your list-building mechanism going, and soon you'll find you have lots of people to whom you can send your creative emails. You still may not know whether that tree in the forest makes a noise, but at least you'll have plenty of customers and prospects listening.