Search engine marketing is on fire. While the media continues to expose its success, more companies are learning how to achieve top keyword positions in search engines such as AOL, Google and MSN. But caught up in the excitement, growing businesses can be lured into a program that's not the real deal: browser-based keyword advertising.

However, not all consumers type in a URL to visit a search engine site. Some enter keywords into the address bar of a browser such as Microsoft's Internet Explorer. For example, instead of typing "www.nike.com" as the URL, consumers type "shoes." An advertiser can buy this keyword. When consumers type it into the browser's address bar, they'll be redirected to the advertiser's Web site. Third-party companies, not Microsoft, sell this service. But it doesn't measure up to buying keywords directly from the search engines.

Brian Yui, founder of HouseRebate in San Diego, spent 0 on this type of program for three, two-word real estate phrases. He received little traffic and found no customer support. Yui is giving another vendor a try, but he's not optimistic. With the second vendor, he also noticed an increase in pop-ups after he downloaded a plug-in. That's problem No. 2: Many vendors deliver more than the plug-in; users unknowingly get adware. Affectionately called spyware or scumware, these programs profile users' Internet behavior to serve them ads, often in the form of those beloved pop-ups.

Besides, consumers without the plug-in might be redirected to Microsoft's own search engine anyway. At the time of this writing, a search for "shoes" sends consumers to MSN's search results page. Learn how to get your Web site to appear here. In the meantime, ignore the e-mail spam from third-party vendors that promotes buying keywords in Microsoft's browser.