You probably have a fairly robust website. And you may know how many people visit. But chances are that your knowledge ends there. Do you know exactly what people do when they get to your site? Which clicks are real and which are bogus? How your site ranks on search engines? Enter Web analytics software, which is designed to parse the volumes of data that a website generates. There's a tangle of vendors to consider; the tech consultancy Gartner estimated in 2006 that more than 70 firms, many of them start-ups, were offering Web analytics tools. Here are six we like the best.

Best for… A performance snapshot

Google (NASDAQ:GOOG) Analytics

What it is: The search giant's Web analytics tool.

What's cool: It's free. It can provide 18 ways to segment data, allowing you to home in on visitors--by keyword, browser, location--and can generate 82 different reports in 17 languages. Online support is strong, especially the Conversion University, a Web-based tutorial for business users.

Drawbacks: You might think that 18 categories and 82 different metrics would be comprehensive, but such is the state of analytics these days that Google's tool qualifies as relatively basic. Also, because it's free and widely used, there's a good chance your rivals will be using it as well, which has the potential to erode your competitive edge.

Price: Free

Best for… Understanding your customers

Omniture (NASDAQ:OMTR) SearchCenter

What it is: A hosted service that analyzes the way visitors behave on your website

What's cool: SearchCenter helps you fine-tune search engine advertising by measuring things such as how long people spend on your site, where they go while they're there, and how that behavior varies according to factors such as the keyword they used to find you. The software works with more than 50 different search engines and their affiliated sites and supports six languages, making it easier to run global campaigns.

Drawbacks: SearchCenter is powerful, but it's also complex, and companies without in-house marketing and campaign management specialists may find its use difficult.

Price: Prices start at about $520 a month.

Best for… Fighting click fraud


What it is: A Web-based tool to ferret out click fraud.

What's cool: Which clicks are real and which are bogus? Click Forensics helps you determine that, analyzing things like how much time visitors spend on your site (if it's only a second or so, the click likely is fake) and whether you get repeated click-throughs from specific Internet addresses. Using that data, you can block clicks from certain senders. The company also collects and publishes click-fraud data from its 3,000 customers, providing a reality check on what the search engines claim.

Drawbacks: Click-fraud artists are wily and fast moving, but Click Forensics updates its data only once a month, so it might have a hard time keeping up.

Price: Free, for under 100,000 clicks a month; $500 for 100,000 clicks per month or more.

Best for… Perfecting your pitch

BetterPPC AdTest

What it is: Software to help you develop better Web ad campaigns

What's cool: It automatically test-markets ad copy. You provide three headlines, three opening lines, and three secondary lines, and it determines which of the 54 possible combinations work best. In other words, it's easy to figure out whether "20 percent off," "Free shipping," or "Buy one, get one free" will drive more sales.

Drawbacks: It works only with Google AdWords, though support for Yahoo (NASDAQ:YHOO) and MSN (NASDAQ:MSFT) are promised by midyear. It does not work for other kinds of Web campaigns, such as banner ads and e-mail campaigns.

Price: $30 for one test; $299 a month, with unlimited testing, for up to $30,000 of ad spending

Best for… Boosting your search engine rankings

WebTrends' WebPosition 4

What it is: Software to help you get better placement in lists of search engine results.

What's cool: WebPosition drills deep into your company's presence on search engines, telling you which keywords generate the highest placement and providing recommendations on how to tweak your site and keywords to improve that position. It automatically shows your site's ranking in more than 200 search engines.

Drawbacks: WebPosition integrates only with WebTrends analytics software. So if you're using, for instance, Google's analytics tool, you won't be able to integrate WebPosition's data into your overall Web reports.

Price: $149 for the standard version; $389 for the more feature-rich professional version

Best for… Coordinating ad campaigns

Coremetrics Online Analytics

What it is: Web-based software to measure and manage marketing efforts, including search engines, banners, and e-mail

What's cool: Coremetrics provides data in a number of categories, including website content analysis, RSS feeds, blogs, site layout, and even whether your on-site search engine is delivering good results. It also offers a benchmarking service, so businesses can compare their results to the average for similar companies. Coremetrics claims most customers get a return for their investment in less than 12 weeks.

Drawbacks: It ain't cheap. And like most powerful software, it's tricky to install and use.

Price: Fees are based primarily on monthly page views; at the low end, clients pay about $24,000 a year. There's also a one-time setup fee, determined by the size of your site (it averages about $6,000).