A couple of weeks ago, my mom asked me to put a tracker on our Web site so we could see who was visiting. I was kind of dreading this. I had put Google AdSense on for a few days -- enough to realize that our traffic was miniscule -- and the ads for "Obama dollars" and "free government grants" made us look like a scam site.

I didn't want to put AdSense back on the site, so I looked around for another way to track visitors. I discovered a range of options from paid to free. They all used software to analyze traffic on a Web site. Where was it coming from? How long did visitors stay? Did they ever come back?

I ended up choosing Google Analytics, which is a cinch to use and seems to tell you the same information as more expensive solutions. Google Analytics is free up to five million page views per month per account.

To sign up I went to http://www.google.com/analytics. The first thing to do is get a Google Account. This is a single sign-in that you can use to access everything from Gmail to Blogger (Google's blogging platform) to YouTube to Google Docs. If you don't have a Google Account, signing up for Google Analytics by providing an e-mail and password will create one.

I already had a Google Account so all I needed to provide to Google was the URL for our Web site and our time zone. When I was done I clicked "finish." Google displayed a box with tracking code that I needed to paste onto my site

People with regular Web sites can just copy this code, which is few lines of Java Script, and paste it before the </body> tag of each page they want to collect data on. Another option is to paste the code into a common template, if you have one. We use Blogger, so this was the best option for us. After logging in, I clicked on the "Layout" tab and then on "Edit HTML." Google displayed a page with two choices. The first was to Backup / Restore a template, and the second was to edit the template. I chose the latter. I scrolled down to fine the (/body> tag at the end of the page, and I pasted the tracking code immediately before it.

It took 24 hours for Google to process the edit and to start showing data. As I feared, our traffic light. But even without a few visits, the power of Google Analytics was impressive, and I could understand why so many people recommend it. The first page you see is an overview, which gives you a quick snapshot of how your site is doing.

THE METRICS

Status. This item lets you know whether Analytics is working. If there is a green check mark in the box then all is well.

Visits. This item lets you now how many visitors you have had during a particular day, week, month or year.

Average Time on the Site. This item tells you how many minutes, seconds or hours that visitors are spending on your site.

Bounce Rate. This item tells you about your visitors' loyalty. It represents the percent of visitors that are leaving immediately after they arrive. In our case, it was about 50 percent. Ouch. That is either a sign that we are attracting the wrong kind of visitors or that our site is not very good yet.

Completed Goals. This measures whether or not you have been successful at persuading your visitors to take certain desired actions. They include making a purchase, signing up for a newsletter, filling out a contact for, reviewing an "About Us" page or reading a particular news article.

Percent change. This item was the bright spot for us. It lets you measure how a particular metric like "visits" or "average time on site" has increased or decreased during a particular time period. In our case visits had gone up 400 percent. Of course, at this point, the only direction we can go is up. But still, I'm of the belief that any victory, no matter how small, is worth celebrating.

To experience the full power of Google Analytics, click on the "view report" link on the overview page. This will take you to the dashboard. This is where you drill down to get the nitty gritty details about who is visiting your Web site and what they are doing there.

The first item on the dashboard is a customizable graph. This will show you on a day-by-day basis how many visits you have had, how many page views, the pages per visit, the average time on site and more. To select the kind of information you want, simply click an arrow in a tab on the top left corner of the graph. An advanced segment lets you filter the data by new visitors, return visitors, paid traffic, iphone traffic and more. You can export the data by creating a PDF or emailing it to yourself or anyone you chose.

Site usage is a summary section directly below the graph. It gives you the total number of visits, page views, pages per visit, etc., for the time period you select.

The Visitor Report compiles all the information your Web server can learn about your visitors, including what browser software they are using, whether they are connecting to the Internet using a cable modem, DSL or a dial-up connection and where in the world they are coming from. You can find out if they were referred by a search engine or another site, or if they came at the prompting of an e-mail.

Whenever someone requests information about your Web site, a separate copy of that request is sent to Google. Google then installs a "cookie," or a very small piece of software code, in your visitor's browser. The code helps Google understand which requests are from the same person and which are from different people.

If I wanted to double check Google's accuracy, I could have gotten similar information from the following services:

Statcounter is free and similar to Google Analytics.

OneStat.com has free software that will count the visitors to your site, but it is less sophisticated than Google Analytics. For a $10.42 a month, it will track visitor behavior, search engine referrals and the performance of sales and marketing campaigns.

Site Meter provides very similar information to Google Analytics and charges a monthly rate of $6.95 for up to 25,000 page views.

You can find a list of more trackers, including trackers for enterprise Web sites at Mashable. One warning: this is one of the best sites I could find listing the various analytics tools, but much of its information is old.

There is one obvious drawback to using Google or other tracker: You are giving your secrets away. When you ask Google to help you figure out who is visiting your site, you need to be aware that you are also telling Google who is visiting your site. When this information is aggregated from hundreds of millions of Web sites it becomes super valuable. Indeed, the data is worth so much to Google that it is willing to provide the Analytics service for free in exchange for it.

The data helps Google target advertising and fine-tune the accuracy of its search results. For example, consider a person, lets call him Sam, who types "cheesy party favors" into the search box and then clicks on a link for miniature party cheese cakes. Sam spends half a second on the dessert page and immediately returns to Google and clicks on a link for "evil genius tees." When Sam arrives at the Evil Genius Web site, the first thing he clicks on is a link for "rude toddler tees." At this point, Google can be reasonably sure that Sam was not looking for diary products, and try to sell him whoopie cushions and fake barf.
Helping Google get smarter could conceivably make good business sense for you, particularly if your site relies on Google's AdSense and you are splitting the proceeds from the plastic vomit sales.

But Web site owners still need to be aware that once they give their data to Google, they can never get it back. And the assurances that Google gives about how it will safeguard the data aren't exactly ironclad. According to the Google Analytics Terms of Service, Google will not share the data you provide until it has a "good faith belief" that doing so is "reasonably necessary to protect the rights, property or safety of Google" or unless third parties need it "to carry out tasks on Google's behalf."
Personally, the benefits for me outweigh risks. If that ever changes, I'll simply remove the tracker. Owners of bigger, more lucrative Web sites may feel differently.

The other thing to keep in mind is your obligation toward your readers. Web site owners are expected to disclose what data they are collecting and for what purposes. You probably won't get penalized if you don't do this, but it is considered a best practice. Google's Terms of Service require users of Google Analytics to post a Privacy Policy statement that notifies their visitors that they are are using a cookie to collect "anonymous traffic data." You might want to be more explicit that you are using Google Analytics to track where your visitors are coming from and how long they stay on your site.