7. Expanding Ads
Another type of ad that's growing in popularity looks like a regular static ad running on the side or top of Web pages. Yet these ads are anything but ordinary. If you mouse over them, they spread across your screen, taking over your browser window. When you move your mouse away, they slither back to their original, unassuming size.
These ads are getting even slicker, now featuring audio, video, and interactive games. The ads are typically on sites that cater to younger demographics--people, EyeWonder's Scheidt says, who may like such rich media ads.
I don't know about you, but I'm never happy when I accidentally roll my pointer over the top-right corner of a Web page and a Flash animation pretends to peel back the page and show me an ad. Unfortunately, I have to deal with these on my own online home: PCWorld.com runs this type of ad on occasion as well.
8. Personal and Tailored Ads
The behavioral-advertising business is booming with major online ad companies, with DoubleClick leading the pack. These companies give me the creeps, because they track my Web whereabouts and likely know more about my surfing habits than I do. Many create digital dossiers of online users that advertisers can use to show you ads tailored to your online activities.
The move toward behavior-based marketing is a trend, says Greg Sterling, an analyst with mobile market research firm Opus Research in San Francisco. That trend motivated Google to acquire DoubleClick, with the intention of targeting and selling ads more effectively. Privacy activists, of course, are foaming at the mouth, concerned that Google and DoubleClick will know too much about Internet users.
This approach marks a shift from the online advertising model Google established, which displays ads based on a person's keyword searches.
To counter the trend, many privacy activists are urging the Federal Trade Commission to create a "Do Not Track" database; consumers registering there could opt out of being tracked by DoubleClick and other online marketers.
9. Malware-Laced Ads
No question about it: Online ads that deliver malicious software are beyond merely annoying. Security firm ScanSafe tracks dangerous banner ads that have shown up on MySpace, PhotoBucket, and other leading sites. Such parasite ads typically contain a Flash file that silently installs a Trojan horse or backdoor program on vulnerable Windows systems. Reportedly, 12 million such ads came from RightMedia, an advertising firm in which Yahoo owns an 80 percent stake.
The most devious aspect of these ads is that they require no interaction from you, and Web sites sometimes deliver them innocently. They often come from third-party ad suppliers that act as middlemen between Web sites and advertisers. Sometimes the company delivering the ads to a site is unaware that a bad-apple advertiser has embedded Trojan horses in them. By sheer bad luck you could visit a Web site that inadvertently hosts a Trojan horse ad, and risk infection, says Mary Landesman, a senior researcher at ScanSafe.
"We find this stuff all the time," Landesman says. "We could report one every week."
10. Bait, Switch, and Infect Ads
A related type of online ad is the kind that entices you with too-good-to-be-true offers. Such messages predate the Web, of course, but online they cause a lot of grief, notes Paul Piccard, director of threat research at Webroot Software.
Earlier this month the Web site of the Arizona Daily Star in Tuscon was hit with a "maliciously coded online advertisement," according to the newspaper's own report. The Star reports that the online ad was purchased by a company using a fraudulent credit card. The ad appeared on the newspaper's site for 18 days and "directed some Web visitors to sites that could have installed harmful software," says the Star's report.
Piccard says that such ads typically promote free software or another giveaway, trying to drive traffic to a booby-trapped Web page. If you click on such an ad, it whisks you away to a Web site that attempts to install malware onto your system through Web browser security holes.
As the Arizona Daily Star will attest, these ads can make their way onto legitimate sites and cause havoc. Piccard says that the malicious payloads these ads deliver to PCs include keyloggers (which collect and send personal identifying financial information), adware, and spyware.