It's been some 15 years that I've been involved in online customer acquisition, having started my journey in 1996 in the "Wild West" days of the 'Net. I've seen technologies and platforms come and go and have learned quite a bit about what works and what doesn't.If there's one overriding lesson, it's that everything you do online is truly a double-edged sword. If you do it right, the rewards are great. If you do it wrong, the results can be disastrous. Consumers can praise you as well as diss you, and they can do both fast and easily. Here are a few examples to illustrate this point:Paid SearchIf you do it right, SEM is one of the most efficient direct response customer acquisition vehicles ever created. But "doing it right" truly is rocket science as I have learned, and requires a number of trained analysts and strategists to squeeze every ounce of profit out of every keyword.If you do it wrong, it could be a waste of money, and your competition can swoop in and eat your lunch. In our Executive Brief "The Search Continuum" we lay out 4 consumer expectations that must be met. Fail to do so and your SEM program is in trouble.What could happen if you do it wrong? How about a Facebook post that goes out to 100,000 fans along the lines, "I can't find this company online. I'll buy it elsewhere."EmailIf you do it right, email can be a fabulous source of new customers and works great for retention. The Direct Marketing Association indicates that ROI for email is over $40 for every dollar spent.If you do it wrong, email can be a major prospect and customer turnoff. If you email too often or your messages are not relevant, recipients will start unsubscribing and ignoring your email blasts, leading to lower open rates and conversions.What could happen if you do it wrong? How about a Tweet that goes out to 10,000 followers along the lines, "Stay away from this company. They bombard you with irrelevant emails every day."Facebook, Twitter and Other Emerging PlatformsIf you do it right, these new media options can be a valuable part of your overall customer acquisition program. But you've got to take the time to understand how they fit in.If you do it wrong, you could be wasting time, money and effort, possibly at the expense of proven acquisition methods. One of the mistakes we observe is executives becoming enamored with "the latest" tactics, long before they are proven to actually work.What could happen if you do it wrong? How about the CEO asking you, "Why are we spending money on this? Do you have any evidence it's paying off?"ConclusionThink of everything you do online as a sword that can cut either way. It's particularly important because everything moves so fast. Changes happen every day &#8211; and you've got to react to them appropriately. Take Google's announcement last week (11/2/11) about a major change in the way paid search ads will be displayed. Is your search team or agency on top of that?The bottom line: make sure you have the right people to strategize and execute on your acquisition game plan, including online and offline tactics. Make sure they understand how online is impacted by offline. Make sure your in-house teams and outsourced agencies are all on the same page, so that you live by the sword, not die by it.Grab a PDF of this article: http://A85.acquirgy.netIrv Brechner has written over 100 published direct marketing articles and 13 books on a variety of topics. He's been a pioneer in online customer acquisition since 1996 and offline for his 35-year career. He has developed Acquirgy.com's "Customer Acquisition Intel Center" (acquirgy.com/intel ) he evangelizes best-of-breed tactics to help companies acquire customers in the digital age. He can be reached at: firstname.lastname@example.org .Read all Irv's MediaBizBloggers commentaries at Customer Acquisition Intel.Check us out on Facebook at MediaBizBloggers.comFollow our Twitter updates @MediaBizBloggerThe opinions and points of view expressed in this commentary are exclusively the views of the author and do not necessarily represent the views of MediaBizBloggers.com management or associated bloggers. MediaBizBloggers is an open thought leadership platform and readers may share their comments and opinions in response to all commentaries.