The whole reason email marketing is done: to drive clients to your web site, where you can sell your products and services to them. But in order to bring them to your site, you need to have addresses to mail those exciting messages to. You can always buy or rent email lists, but this isn’t always 
best strategy. It’s expensive, and there’s no guarantee that company you choose got their addresses legitimately. Opt-in email lists (people who ask you to send them information) are always a better method for marketing purposes, and you have a guaranteed target audience.
Increasing your opt-in list of targeted email clients is most important email marketing strategy you can use. Your email list is actually a group of potential "sales leads" and you should treat expanding your email list in same manner you would your leads offline: develop it, and develop it aggressively.
The more effort you put into developing it, more potential customers you will have. Conversely, if you fail to collect email addresses, your online business growth will halt. It’s that simple.
Tip #1: Offer Them Content
People don’t just like to give out their email addresses online (and with good reason nowadays!) But if you offer them something in return, such as an informative newsletter, a free ebook, or free software, they will be much more likely to give you their email address when subscribing.
Offering subscriptions, whether to a newsletter, ezine, ebook, software, or online course, is number one legitimate method of increasing your email list (and is used by all of largest and most successful sites online). People have indicated that they go online for a major, basic reason: to learn. Are you meeting this need? You will be, if you offer them high-quality information through one of above methods.
Don’t just send them ads (unless they have specifically requested news on current specials); spice it up with information that they can use. They will remember you, will pass your newsletters around to their friends, and your name and company will get known.
Tip #2: Make It Easy For Them
It’s amazing number of sites that have subscription forms tucked away deep within their site hierarchy, or don’t even have interactive subscription forms for signing up. Don’t just rely on customer taking initiative of sending you an email asking to subscribe to your content; have a web designer create an easy-to-use form that they can fill in and subscribe to.
Place your subscription box in a prominent area. Normally, left top side of a web site is area that a visitor looks at first. This is a natural area to place a small box that says, "Subscribe to our informative newsletter" or "download our free software" to increase your email list. Alternatively, you could create a pop-under that appears before they leave, asking if they would like to subscribe to your quality content. Don’t let them leave your site without offering them chance, with an attractive ad, to sign up - and give you their email address.
Be sure to have a link on each and every web page on your site, offering visitors chance to subscribe. Otherwise, they may go to your site, click around, and by page four, forget that they meant to sign up for your newsletter or ebook. Remind them frequently with a tasteful link or box on each page, and watch your subscriptions rise.
Tip #3: Assure Their Privacy
When a person visits a web site online, they often hesitate to give out their email address. Since they don’t know you, they often fear worst: that you could be an unscrupulous email harvester, who will turn around and sell their information to sleazy porn sites or lending companies charging high interest rates.
Of course, you don’t do this, and one way to overcome this natural hesitation is to place a prominent privacy notice near your subscription form that states: "Your privacy is important to us. We will never sell or disclose information that you provide us with." You have just overcome number one reason that people don’t give out their email address, and increased greatly chances that your opt-in list will grow.
Tip #4: Don’t Use Force, and Don’t Ask for Too Much Information
Nowadays, some sites have become quite aggressive in their techniques for getting email addresses, to point that they won’t allow you to enter their site without giving it. Most people will click away from sites that use techniques that don’t offer choices. Instead, make subscription their choice, and never, ever force issue.
