"Search engine marketing took fire in our industry faster than in most others," says Brian Elliott, Chief Operating Officer for Alibris, a supplier of new and used books, music, and videos. "It's not a high margin sale so you can't afford to spend $50 to acquire a customer."

While Alibris continues to make a positive margin on paid search, "it's not the growth engine it once was," Elliott says. Still, he buys "about a million terms."

Here are four tips Elliott offered on keeping paid search a viable tool in the increasingly competitive marketplace.

-> Tip #1. Don't let affiliates buy your name

Alibris has a large affiliate program, with one major rule: No buying our name, says Elliott. "We discovered that almost two years ago. It's a money-losing proposition."

He doesn't limit affiliates in terms of words and phrases such as author names, however.

"If an affiliate buys a really common author name and then refers traffic to us and the conversion rate is awful," says Elliott, it's the affiliate who is losing money.

-> Tip #2. Consider what searchers are *really* looking for

"Our illustrious governor has written a book or two, but when most people enter his name into Google, they're looking for something else," Elliott says.

In other words, buying the phrase "Arnold Schwarzenegger" doesn't work.

There's also a book called "Propecia: The Hair-Growth Breakthrough," but again, when people type in "propecia," they're generally not looking for a book.

-> Tip #3. Reduce merchandising on landing pages for broad search terms

The less people know about you, the more you need to test how you orient them on your site. If a user typed in the term "used books," they probably don't have a totally clear idea on what they're looking for.

In that case, Elliott would want them to land on a page that talks about what Alibris does and what a visitor will get by exploring their site. "We'd skinny down on the amount of merchandising and fatten up the search aspect of the site and the description of what it is we do," he says.

You might want to experiment with whether you should land those broad searchers on the home page, on the "About Us" page, or on the general used books category page, for example.

-> Tip #4. Test "buy" button placement

After you've tested where you are landing people who search with broad terms, work your way down to specifics. "People who search for the name of the product or an author's name, whenever feasible you want them to land them on that product," Elliott says. "The 'buy' button should be sitting there right in their face so they can make a purchase decision."

Note: Alibris is a member of Shop.org, a forum for retailing online executives to share information, lessons-learned, new perspectives, insights, and intelligence. More info at http://www.shop.org