Follow these techniques for building your opt-in and marketing lists:

1. Offer a free newsletter. When you give individuals something of value in exchange for an email address, you'd be surprised at the subscription rate. Offering a free newsletter that provides valuable information can generate a large number of opt-ins.

2. Require registration. Many sites offer white papers or access to valuable reports but only in exchange for a registration. When offerig something of value in exchange for information, ask individuals for their email address prior to download. This is also a great opportunity to ask these individuals to "opt-in" for additional information or notifications.

3. During the registration process. Do you ask individuals to register on your site when buying a product or prior to accessing particular features of your website? When individuals register and offer an email address you are technically allowed to email them at least once. However, by adding additional opt-in fields, individuals may choose to sign up to receive additional information from you or your website for specific information.

4. Co-Registration. Do you have something of value to share with other websites? Perhaps you can provide your web tool to other websites who could benefit, requesting users to sign up prior to using the tool. When they do, you can share these opt-ins with partner websites.

5. Transactional Emails. After an individual has bought a product from you, use transactional emails to determine which of your customers are ready for marketing messages for other products or services provided by you or another vendor. By asking for this information on a transactional email, you are more likely to increase response rate and ask if users would like to hear about specific products from vendors or partners.

These are just a few ideas you can use to improve your opt-ins and/or build a more targeted email list. If you have other ideas, share them by leaving a comment to this post.