I haven't seen it on the web, but an article in my local newsrag was a bit worrisome. They only post stuff on their website for about a week and then you have to pay to see it, so no link, but:

[quote from scan/OCR]

CenturyTel Inc., a Monroe, La., phone company that provides Internet access and long-distance calling services, is facing stiff competition from cell phone companies and cable operators. So to diversify, it's getting into the online-advertising business. And not just any online advertising. The technology it's using could change the way the $16.9 billion Internet ad market works, bringing in a host of new players — and giving consumers fresh concerns about their privacy.

CenturyTel's system allows it to observe and analyze the online activities of its Internet customers, keeping tabs on every Web site they visit. The equipment is made by a Silicon Valley start-up called NebuAd Inc. and installed right into the phone company's network. NebuAd takes the information it collects and offers advertisers the chance to place online ads targeted to individual consumers. NebuAd and CenturyTel get paid whenever a consumer clicks on an ad.

This technique — called behavioral targeting — is far more customized than the current method of selling ads online. Today, it's an imperfect process: companies such as Revenue Science Inc. and Tacoda Inc., which was bought by Time Warner Inc., contract with Web sites to monitor which consumers visit them, attaching "cookies," or small pieces of tracking data, to visitors' hard drives so they are recognized when they return. The targeting firms feed the data to Web site owners, who use it to charge premium rates for customized ads. But the information is limited, since the tracking companies can't monitor all of the sites and individual visits.

The newer form of behavorial targeting involves placing gear called "deep-packet inspection boxes" inside an Internet provider's network of pipes and wires. Instead of observing only a select number of Web sites, these boxes can track all of the sites a consumer visits., and deliver far more detailed information to potential advertisers¹.

Until now, the booming online ad market has been dominated by the likes of Google Inc. and Microsoft Corp. and small techie advertising shops such as Right Media Inc. and AdECN Inc. But new companies are rushing in. Both wireless and wireline Internet-access providers such as CenturyTel, Rochester Telecom Systems Inc. and Embarq Communications Inc., among others, have entered the advertising gold rush. And they've tapped Internet equipment companies like NebuAd, FrontPorch Inc., and Phorm Inc. to provide the gear to help them along.

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¹ to potential advertisers ... and to police, government agencies, your current or prospective employer, ex-wives, your health insurance provider, your bank and/or credit bureau(s), your psychiatrist, and/or the private investigator hired by anyone who has a "bad feeling" about you?

John