Whether you want to trumpet a new product, spread the word about a sale, or simply say, "Hey, [first name], you are important to us," e-mail marketing is a great way to interact with customers. Here's our pick of services that let you manage subscriber lists, comply with spam regulations, monitor bouncebacks, and obsessively track who opened and clicked on what. Some of these will even check your message against spam filters, ensuring it won't share the same junk-folder fate as the Viagra offers. But it's up to you to give your missives enough zest--and give enough breathing room between dispatches--so that customers don't click Unsubscribe.

BEST FOR: Beginners

WHAT IT IS: Web-based software for sending bulk e-mail blasts

WHAT'S COOL: You don't need to be a technical or marketing whiz to get started. Just import a list of contacts with the help of an online tutorial, customize one of 200 design templates, add your content, and click Send. The service tracks how many people open your e-mail, click on links, or opt out. Plus, Constant Contact offers a 60-day free trial and a monthly newsletter with tips on things like how to avoid spam filters and the best time of day to send messages.

DRAWBACK: Though you can add your own images and change colors, the templates are pretty basic.

PRICE: Ranges from $15 per month for unlimited e-mail blasts to 500 addresses to $150 for 25,000 addresses. Pricing is custom for larger lists.

BEST FOR: Sending text messages

WHAT IT IS: A service that sends bulk e-mails as well as text messages to cell phones

WHAT'S COOL: MobileStorm helps you communicate with customers in a variety of ways, including by text message and e-mail. When sending text messages, you can use MobileStorm's five-digit short code to let customers sign up via text message for your notifications. You can even tailor the service to automatically send a confirmation text message when a customer, say, edits his account information or makes a purchase. Every text message allows customers to unsubscribe.

DRAWBACK: The pricing is similar to cell phone plans. Send more e-mails or text messages than are included in your plan, and you'll pay overage fees.

PRICE: Starts at about $20 per month for 1,000 e-mails and $35 per month for 250 SMS text messages

BEST FOR: HTML experts

WHAT IT IS: Web-based software for sending e-mails designed in HTML

WHAT'S COOL: If you have an in-house programmer who can design your message in HTML, Campaign Monitor makes it easy to send out a sophisticated campaign. Upload the code or type in a URL, and if you have forgotten to add any requirements, like Unsubscribe links, it will offer to add them for you. For an extra $10 per blast, Campaign Monitor will test how your campaign looks on popular e-mail services and how well it gets through major spam filters.

DRAWBACKS: The company offers some simple templates, but you really need Web-design experience to create anything decent. If you frequently e-mail a lot of customers, the fees add up fast.

PRICE: $5 per blast, plus 1 cent per recipient. E-mailing 100 recipients would cost $6, while e-mailing 100,000 recipients would cost $1,005.

BEST FOR: Reaching the Facebook crowd

WHAT IT IS: A tool that makes it easy for customers to forward your e-mails to their friends

WHAT'S COOL: Pop Commerce lets your customers forward your e-mail offers to their Outlook contacts and Facebook friends in just a few clicks. For selling out their friends, customers usually get a kickback--say, a $25 gift certificate if they send your coupon to 10 people. You can watch your subscriber base grow as the social-networking junkies pass around your offers. You can also keep tabs on--and reward--your most zealous patrons.

DRAWBACK: Unless your customers are young, a viral marketing campaign targeting social networks may not earn a high return on this large investment.

PRICE: Pricing is custom. A typical contract lasts several months and runs from $50,000 to the high six figures.

BEST FOR: Getting design help

WHAT IT IS: A Web-based service that designs the basic look of e-mails for you

WHAT'S COOL: You can create polished-looking e-mails without any technological prowess. Emma's designers create a custom template for your company using your logo and company colors. Then, for each campaign, you use Emma's software to add photos and text. Emma can create a branded page for your website, where customers can sign up for communiqués. It also provides tools for managing your subscribers and tracking deliveries.

DRAWBACK:Don't expect Emma to create a whole new branding look. It's only as good as your existing branding designs.

PRICE: $250 for the template design, plus about $30 a month to send up to 1,000 e-mails and $600 a month for up to 100,000. Sign an annual contract and you'll get 10 percent off.

BEST FOR: Heavy users

WHAT IT IS: An e-mail server loaded with software that's optimized to blast e-mails to millions of customers

WHAT'S COOL: In addition to delivering huge volumes of e-mail, StrongMail's software screens for invalid e-mail addresses as well as words and phrases that might get messages blocked by spam filters. It also generates detailed metrics on click-through rates and bounced e-mails. It can be programmed to work with a company's other applications, such as CRM software. This type of system is well suited for companies that rely on e-mail newsletters as a large part of their business.

DRAWBACKS: Setting this up is a big internal IT project, and it costs a big chunk of change.

PRICE: From about $30,000 for small businesses. Prices can exceed $1 million for larger companies.

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