A lot of dangers threaten you on the Internet--even when you're just browsing Web sites. McAfee's SiteAdvisor Plus, the for-a-fee sibling of the company's free SiteAdvisor product, and Symantec's Norton Confidential focus on protecting you while you interact with Web sites. SiteAdvisor, the cheaper of the two, protects against a wider range of threats, but its blanket approach to site blocking is a serious limitation. Norton Confidential targets phishing and has a password manager; unfortunately, it costs nearly as much as a full-blown security suite, which neither of these programs can replace.

I tested a prerelease version of Norton Confidential (version 1.0.0.2) and a final version of SiteAdvisor Plus (version 1.7.0.53). Both products use a color-coded safety rating to categorize Web sites you visit. As you surf, Norton Confidential places a large, oval indicator--green for good, red for bad--within a browserwide toolbar. SiteAdvisor's petite toolbar does the same for good and bad, and adds two more colors: Yellow indicates a questionable site, and gray indicates an unknown site.

Unfortunately, these programs only work with Internet Explorer 6 and later. In fact, with SiteAdvisor Plus enabled, you can't use Firefox at all. McAfee plans to support Firefox by the end of the year; Symantec says it's working on a Firefox version, but has not fixed a specific completion date for it.

The two products take different approaches to protecting you. SiteAdvisor Plus, like the free--and Firefox-compatible--version of SiteAdvisor, checks sites against a vast database of sites that McAfee has previously tested for adware, spyware, viruses, phishing, and spam. The primary reason to pay $25 for SiteAdvisor Plus is to get its Protected Mode, which blocks users from visiting sites coded red and yellow. Since yellow sites are only suspected as dangerous, possibly as a result of unverified user comments, blocking them en masse seems a bit draconian. I would be happier if SiteAdvisor Plus let you choose to limit the blocking to red sites only.

SiteAdvisor Plus also flags suspect URL links embedded in e-mail and chat clients. At press time, SiteAdvisor supported Yahoo Messenger, Windows Live Messenger, and Google Talk chat clients, as well as Outlook, Outlook Express, Gmail, Yahoo Mail, and Microsoft Live Mail (Hotmail) e-mail clients. Notably missing are AOL Instant Messenger and AOL Mail; McAfee expects to support the current versions of each by the end of year.

SiteAdvisor's Protected Mode will protect you from sites suspected of distributing adware and spyware, but Norton Confidential won't. That's because Norton Confidential focuses on blocking phishing sites that try to steal sensitive personal information. To accomplish that, it checks sites against its own previously conducted research; analyzes sites in real time; and watches for keylogging, screen capturing, and data mining. And whereas SiteAdvisor (paid and free) color-codes search results in Google, Yahoo, and MSN, Norton Confidential does not.

Accompanying Norton Confidential, a password manager called InfoVault stores and backs up online and application log-ins and passwords, using strong 1024-bit RC5 encryption. It automatically fills them the next time you visit the site, too. InfoVault worked perfectly with several of my e-mail, banking, and Web service accounts. But it had trouble with Bank of America's site, which uses two-step authentication.

In informal tests, both Norton Confidential and SiteAdvisor successfully blocked PhishTank.com's list of verified phishing Web sites. But whereas McAfee's blanket blocking flagged everything equally, Norton's messaging differentiated between known bad sites and suspected bad sites; you can choose to visit the latter if you want.

Neither product supplants your antivirus or antispyware program, which may (and probably does) contains antiphishing protection; the full security suites from both Symantec and McAfee have antiphishing components. And neither product blocked a Web site (linked from spam) that sold, shall we say, performance-enhancing pharmaceuticals, so they can't substitute for using common sense while surfing.

If you currently use either McAfee's or Symantec's Internet security suite, I'd skip both of these one-trick ponies, due to the overlap in protection. But if you're looking for a discrete antiphishing tool to protect you while banking or buying online, Norton Confidential wins my vote despite its high price. SiteAdvisor Plus's blocking is less sophisticated, and the informational benefits of SiteAdvisor are available in the free product.