A good on-site search tool is an Internet merchant's best friend.

First, and most importantly, it allows shoppers to find products faster, boosting conversion rate. "All the studies have shown that some people immediately gravitate toward the search field if there is one," says Avi Rappoport, a leading search analyst.

In fact, many shoppers now rely exclusively on a site's search tool. "A good chunk of the search queries on any site comes directly from the home page," she notes — some visitors refuse to navigate through the site. Even when shoppers are seeking a product "that's listed right there on the home page, and it's in fluorescent letters and practically blinking," many users still head right to the search box.

Additionally, on-site search provides merchants with a gold mine of information about what shoppers are browsing for. If a site owner sees a lot of searches for "handmade toy" they can be sure they'll profit from carrying more handmade toys. On-site search "is great for mining information — it's great for keyword research," says Jamie Low of SearchEngineMarketing.

However, many online merchants — especially small and mid-size sites — have an inadequate on-site search tool. "A lot of the e-commerce packages have a little search engine with them," Rappoport notes, but they tend to lack many features that a top search tool needs — and today's shoppers expect good search.

"There are certain expectations that Google and Yahoo are bringing up in people, and a lot of times the old-fashion search tools aren't good enough," she says.

But when e-tailers go shopping for a better search tool, they find plenty of choices and plenty of confusion — along with plenty of expense.

So what, exactly, should a merchant know when they go shopping for an affordable, highly effective on-site search tool?

Test Before Buying
A small merchant should be able to find an effective search tool for under $2,000, Rappoport says, and perhaps under $1,000 if a merchant knows enough to do some of the implementation work. However, she says the emphasis shouldn't be totally on cost saving: a good search tool is a worthy investment.

Indeed, says Jupiter Research analyst Eric Peterson, many companies are lagging on their search tool investment - at the expense of their bottom line. "Too many companies are still trying to do it on their own, with SQL or open source, or homegrown solutions - not proper, packaged search," he says.

No matter what search tool a merchant considers buying, experts strongly recommend trying it out before buying. Most search tool vendors offer a free trial to prospective buyers. "They can sign up for free and try it out, and if they like it they can go up to the paid professional version," Rappoport says. She maintains a list of search tools for e-commerce sites.

Her site, Search Tools, also offers users a page full of search boxes, allowing users to try them all out side-by-side. The results offered by each tool are remarkably different, with some giving about a dozen results, and some offering more than a hundred.

One bit of lingo to know: many small and medium-sized sites are using a hosted search solution, which is a search tool that resides on the vendor's server, but is dedicated to searching that merchant's site. One advantage of a hosted solution: the search vendor can more easily offer upgrades, without the merchant having to re-install any software.

One bit of advice: merchants tend to make some common mistakes in implementing on-site search, Rappoport notes. "The number one mistake is that they don't have good titles to their pages." Each page's title should be specific, focusing on precisely what that page holds.

Search Tools: A Zillion Choices
There is no single "right" pick for a search tool. A merchant's choice of search tool depends on how large their site is, their budget, the products they sell, and so on. So it's worth surveying the market before making a choice.

Among low cost solutions, Rappoport points to DTSearch, and popular open source search apps like Swish-e and HTDig, both of which she likes.

For low cost hosted solutions, Fusionbot "is one of my favorites," she says. She also likes Blossom, which provides search for San Diego's Natural History Museum, among others. Both Fusionbot's and Blossom's basic services start at $20 a month. (Fusionbot offers a free version.)

Not surprisingly, Google is a leader in the on-site search market. The company structures its offering into three tiers. At the bottom end is its free search tool, which is highly popular with mom and pop sites. The problem is "it doesn't have many features or control," Rappoport says. "In particular, you have no control over when your site is searched — if you make a change, that change might not be in the searchable index for a day or a week."

Worse, the free Google tool does not allow a merchant to see the list of the words that shoppers are searching for.

(By the way, Rappoport doesn't believe the industry rumor that if a merchant uses Google's on-site search, it will help their ranking in the Google search engine. "That doesn't make any difference," she says.)

A step up from the free tool is Google's Mini, which retails for $3,000. The cost is "quite a lot — I think that's a little much," she says. However, the Mini "has a lot of nice features, and you can get up and running really fast," she says.

In Peterson's view, "The Mini is about as inexpensive as you can get for search that's good." However, "I don't like the Mini for commerce search, but for content search it's pretty good."

The difference between content and commerce search, he explains, is the ability to do attribute-driven search. An ideal commerce-based search tool will intelligently narrow results based on customer input. It won't, for example, show all sweaters, just the red V-neck sweaters, and it knows enough to include maroon and red-striped sweaters.

"Anytime you have the opportunity to help somebody make a purchase by showing them the breadth of attributes available to the product, that creates a different set of needs for the search technology," he says.

Google's top end offering is its Google Search Appliance, which starts at $30,000.

Google's search appliance is "the standard," for content search, Peterson says, but again, he likes it for content rather than commerce searches.

The Google search technology "isn't necessarily better or better or worse than their competitors, like Fast Search & Transfer Autonomy, or a long list of technologies that do regular content search. It's just more familiar because so many people use Google," he says.

"I've talked to any number of companies who use the Google search appliance for content search, and they love it, they love the simplicity," adds Peterson.

Another top vendor in the SMB on-site search market is WebSideStory's Atomz. Atomz has a "relatively high monthly fee, but you get a lot of value," Rappoport says. "I definitely think that WebSideStory is one of the leaders in this field."

Notes Peterson: Atomz "is the most affordable" solution, given the solution's broad range of tools. Also, "It's pretty quick to get up and running."

The Atomz Commerce solution touts its sophisticated merchandising controls, which allow the flexibility to quickly adjust site rankings and relevancy to help drive sales. The commerce search tool starts at $25,000, plus implementation, but the cost "can be different for each client depending on their needs," says Eric Bratt, WebSideStory's communications director.

Mercado's e-commerce search product is highly tunable, says Mercado PR representative Mark Shapiro. The Closed Loop Merchandising tool "allows the user to fine tune the search depending on inventory levels and analytics." Moreover, the company "customizes it for individual customers — they'll sit down and make sure it all works." Mercado's licensing fee begins at $3,500 a month.

SLI-Systems's Learning Search claims to "learn from your customer's behavior and continuously improve the quality of each search experience." The company also has a tool called Site Champion, which is an automated search engine optimization tool; it uses terms that visitors search for to generate keyword links to relevant product pages.

Endeca, clearly a high end, large enterprise option, is considered an industry leader. "Endeca is very expensive, but it stands out by adding a whole bunch of additional features," for advanced search options, Rappoport says.

How to Choose an On-Site Search Tool Before a merchant chooses among the many search tools on the market, Peterson recommends they consider the following:

How much experience does the vendor have with my particular set of problems?: "You don't want to be the first problem they have to solve — you want to be the problem they've solved 50 times."

Look at example sites: Most search vendors link to sites they provide search for; prospective customers should visit theses sites and poke around. "Do you like how the search results look? Does it look like it provides the level of flexibility you need?"

Relevance control: A good e-commerce search tool allows merchants to change the "relevance settings" of their search engine. This enables the merchant to link keywords with given products. "Some of them go so far as to give you the ability to import data from your Web analytics application and tweak the relevance of your results based on popularity," Peterson says. "Others let you bring in information about product margin, if you want to show the high margin results on the first page."

Cost: "Even given all the studies that good search drives consumer purchase, you don't really believe it until you see it for yourself, so you want to be cost conscious," he says. Small business owners are often hesitant to invest large sums, but search may be a place where it's worth it. Many businesses wouldn't consider spending $100,000 on search, "but if you knew it would make you $1 million, you certainly would," Peterson notes.

In other words, "Don't always pick the cheapest solution. But if you're going to chose a more expensive solution, make sure it's worth it." Peterson, again, urges merchants to test-drive a search tool extensively beforehand.

"When companies say 'We're going to get an inexpensive solution for search,' sometimes they end up with open source stuff that doesn't work so well. Or an SQL jockey says 'Well, I can write search' — but it turns out that it's harder to do than anybody thinks. That's why these [search vendors] exist, because it's really pretty hard to do."

Peterson freely admits he's not a fan of open source search tools. "I've talked to companies that are doing an okay job with it, but they have to dedicate resources to managing that solution. And nobody ever told me a story about how open source search changed our business — I've heard the stories of how good packaged search solutions changed their business."

James Maguire is a contributor to ECommerce-Guide.com. His weekly feature appears every Monday.