But simply using SiteAdvisor doesn’t mean you have a 100% guarantee against spware and adware. Yes, it’s a comprehensive, easy-to-use tool that offers significant value to nearly any PC user. But, like any software program, it isn’t foolproof. This in-depth look at the application will provide you with the information you need to have as you rely on SiteAdvisor.

The Basics

SiteAdvisor is a free, small (2.83MB for the Internet Explorer version) tool that you download from the McAfee site at www.siteadvisor.com. Down-load and install the appropriate version for your Web browser or browsers--SiteAdvisor works with IE and Firefox--and a small ratings box integrated into your browser displays a color-coded safety rating. Green means the site is safe to visit, yellow means use caution, and red means you’d be wise to avoid the site.

“It’s a bit of social engineering,” says Shane Keats, McAfee market strategist. “We help the consumer understand that when you go to www.freeipods.com and think you’re getting a free ipod, in point of fact, when you sign up, you get hundreds of emails. This type of site has used the lure of the free come-on.”

When you come across a site about which you have concerns or questions, you can click the SiteAdvisor information button for a link to a McAfee Web page carrying a detailed description and analysis. McAfee lists data such as when the site was established, where it is hosted, and how popular (how many users) the site is. The data also includes information on how many emails you are likely to receive as a result of submitting your address to the site, how many downloads on the site are considered unwanted programs, and what types of links (green, red, or yellow) the site itself links to.

SiteAdvisor also works with popular search engines, including Google, Yahoo!, MSN, AOL, and Ask.com. Not only does the software rate each returned result, giving you the opportunity to view its rating before you visit the site, but SiteAdvisor has also studied the percentage of red and yellow sites returned by each search engine. (In case you’re curious, MSN had the lowest percentage, Ask.com had the highest, and Google fell in between.)

Behind the scenes, an automated system supplemented by manual analysis is conducting regular safety tests of Web sites. SiteAdvisor tests Web sites for excessive pop-ups and other annoyances. It tests downloads for viruses, malware, and other unwanted programs. It completes online forms and tracks subsequent spam messages.

“We built a system that uses one-time use email addresses,” says Keats. “The army of bots goes out there, clicking yes to everything they find. If spam comes in as a result of a sign-up, we know the site is unsafe. It’s an elegant solution to a daunting problem.”

Plus, users both internal and external submit feedback on various Web sites. All this information is placed into a humongous database, and SiteAdvisor relies on this database in categorizing millions of Web sites.

SiteAdvisor Advantages

At this point, you may be wondering why you need a program such as SiteAdvisor when you already have an antispyware program on your PC. One of the main advantages of SiteAdvisor is that it heads off trouble before you encounter it, not during or after. SiteAdvisor can help protect you, as well as other users in your household who may not be as computer-savvy as you are, from even visiting potentially dangerous sites, let alone interacting with them. It’s easy and intuitive to use, because almost anyone will immediately recognize the green/yellow/red ratings system. And, if you have any questions about how a rating came to be, you can check out the detailed description.

Plus, SiteAdvisor’s promise of accuracy is backed by a crack team of developers. In April 2005, a group of MIT engineers built the system of automated “patrollers” that scan the Web and rate Web sites. McAfee acquired the system soon after and continued to develop the technology. It has tested sites that account for roughly 95% of Web site traffic, downloaded and tested more than 2 million programs, and filled out more than 7 million online registration forms. (Keep in mind that this does not mean McAfee has tested 95% of the Web sites out there, but rather that it has tested the sites that account for all but 5% of the Web site traffic.) As the company notes, “If you’re thinking of browsing, downloading, or registering for something online, chances are we’ve already been there and done it.” And, SiteAdvisor’s ratings are based on unbiased information; McAfee does not accept payment for ratings or to change a site’s rating.

Potential Limitations

While we’re sold on the advantages of SiteAdvisor, there are some potential limitations it would behoove you to be aware of. As we mentioned, SiteAdvisor is comprehensive, and it will guide you through Web sites. If you don’t see a red or yellow warning, though, that doesn’t necessarily mean a site is safe; it may mean that SiteAdvisor hasn’t tested it. If you or other users of your PC rely on SiteAdvisor ratings, you’ll want to make sure they understand that while green means go, a lack of yellow or red doesn’t necessarily mean the site is safe.

Another item we recommend you keep in mind is that there is potential for a site to tailor content to fool SiteAdvisor. The back-end program routinely checks and rechecks sites, and McAfee does not publish the frequency of those checks. But if, say, a site were checked every four days (we’re pulling that number randomly out of a hat--the folks at McAfee would not disclose that data to us), and the site is rated green on day one, it could begin propagating spyware on day two and day three while still boasting a green SiteAdvisor rating.

Plus, while SiteAdvisor is based on sound methodology, in theory it isn’t perfect. For instance, consider a screen saver site with thousands of downloadable screen savers. SiteAdvisor doesn’t necessarily check all of those screen savers. Instead, the program might download, say, 10 (again, this is a number we’ve invented) of those screen savers and test them. If all 10 downloads show the same safe behavior, the entire site will likely be rated green, even though much of the content has not been checked.

Keep in mind that SiteAdvisor does not rate sites based on content alone. Let’s say you don’t want children in your home to visit adult content sites. Making sure they visit only green sites, however, will not prevent that from happening. SiteAdvisor doesn’t rate sites based on content. If the site fails SiteAdvisor’s safety test--something adult, game, and screen saver sites tend to do much more often--the site will garner a red or yellow rating.

SiteAdvisor does exactly what the name implies: advise. It doesn’t prevent. If you want to go to a red or yellow site, nothing in this program will stop you. Rather, SiteAdvisor is a guide to safe behavior on the Internet. And just knowing what’s out there can make the Web a lot less dangerous place to be.

by Heidi V. Anderson