In many markets, e-mail has become a more important customer interaction tool than the phone. And for many companies, most of the e-mail sent out is \n\nnot person-to-person: it's sent in bulk blasts. E-mail blasting tools and services are evolving at a very rapid pace, with the product definitions blurring \n\n(particularly when it comes to the marketing automation category). So let's try to get \n\nthings straight.Horizontal BlastersThis is the classic bulk e-mail system that sends the same message out to a very wide range of people. If you're the sender, you may call it "lead \n\nnurturing." If you're on the receiving end, you may call it spam. Since the CAN SPAM law specifies hefty fines for unsolicited e-mail (and common \n\nsense says "don't irritate your prospects and customers"), the first order of business is to make sure that the list you are mailing to has opted in.Of course, the exact definition of "opting in" is a matter of noisy and endless debate. The core concept is that the recipient has expressed interest in \n\nthe topic of your e-mail. Fine&but what do you do when there's a new topic that nobody could ever have opted in to? The best strategy here is to put \n\nan opt-in appeal for the new topic in all your current e-mail blasts (and of course, liberally sprinkle opt-in offers in your Web site).This means, of course, that your CRM system will have to maintain a profile for all leads and contacts of all the horizontal blast topics they're \n\ninterested in. The CRM system's built-in "opt out" flag should only be used for people who've said "never e-mail me again." The topic-interest profile \n\nmust be a custom field shown as a multi-select pick list, so it doesn't consume too much screen real estate.For a company of any size, it's critical to do a full two-way integration between the e-mail blaster's "bounce" and "opt-out\/interest" tables with the \n\nCRM's e-mail address and topic-profile fields. Unfortunately, this is only partly available off the shelf. Expect to write some triggers or data-translation \n\ncode if you have to manage dozens of topics or product areas.Success of horizontal e-mail campaigns hinges on the quality of the list, and the relevance of the content. The interest tables takes care of \n\nrelevance...but the quality of your mailing list is trickier. Most purchased lists have very poor yield: the best mailing list in the world is the one you already \n\nhave. It's the one stored in your CRM system. So groom it and manage it well.Vertical "Drip E-mails"Vertical e-mail campaigns are fully automated as well, but they couldn't be a starker contrast to horizontal campaigns. Vertical campaigns are never \n\ndone to huge groups the way horizontal blasts are. A vertical campaign starts in response to a user action, such as registering on a Web site or \n\nrequesting a download. To work effectively, the vertical campaigns should be highly aligned with the specific area of the customer's interest and done in \n\nfairly rapid sequence. For example, the first drip e-mail might be sent within a few hours of the prospect's action, followed by e-mails 2, 4, 6, and 10 \n\ndays later. In contrast, horizontal blasts may be sent only on a monthly basis.Consequently, vertical mails never suffer from an opt-in problem: the user explicitly asked to hear more about a topic. Of course, you still need to \n\nquickly accommodate opt-out requests, but there's much less worry about irritating prospects.In your CRM system, the vertical campaigns need to be visible to the sales and support team. They need to know what mails were sent to whom \n\nwhen, and whether they've been opened. If there are specific calls to action within the drip e-mails (e.g., "download this free plug-in"), these prospect \n\nactions need to be shown within the lead and contact record as well (typically as a series of activities whose names make an obvious linkage back to the \n\ne-mail).The vertical campaigns should also stop if there has been a phone or other in-person interaction between your company and the prospect. Part of \n\nthe magic of drip marketing campaigns is maintaining the illusion of a person-to-person e-mail sequence. You don't want the robot to actually show \n\nthrough.To make all this work well, you're either going to have to buy one of the fancier marketing automation systems, or do a bunch of integration with \n\nyour e-mail blaster and Website by writing a fair number of triggers for your CRM system.Customer SupportThe previous two use cases were focused on marketing and lead cultivation. But ongoing customer support is another huge use of e-mail. And \n\nincreasingly, these e-mails are being generated automatically.Again, there's no issue of opting in here. You know the e-mail threads are relevant because they were started by a customer asking for help and, are \n\nproviding real-time updates on their case. There's also not a big problem of the robot showing through. It's now commonplace to have support-bots suggesting workarounds and possible \n\nsolutions. That said, you need to avoid a cacophony of uncoordinated e-mails arriving at the customer's inbox. We typically recommend that your \n\nsupport team (and all of their bots) send all e-mails into the CRM system (using a feature like Salesforce.com's e-mail-to-case functionality, or via \n\ncustom code in other systems) so everyone can see the state of play from the customer's perspective. There is a gray area here: when you're marketing a new service offering. Even though your customers may all find your offer relevant, solicitations \n\nmust follow the rules of marketing e-mails, not support e-mails.By keeping all conversations visible to all of your CRM users, you dramatically reduce the likelihood of duplicate or confused messages getting to \n\nyour customers and prospects. This is one of the most important steps to highly effective CRM \u2014 and great customer interactions. David Taber is the author of the new Prentice Hall book, "Salesforce.com Secrets of Success" and is the CEO of SalesLogistix, a certified Salesforce.com consultancy focused on business process improvement through use of CRM systems. \n\nSalesLogistix clients are in North America, Europe, Israel, and India, and David has over 25 years experience in high tech, including 10 years at the VP \n\nlevel or above.Follow everything from CIO.com on Twitter @CIOonline.