Over the weekend, a small storm erupted over new legal language that Verizon Wireless is passing quietly on to its subscribers. It appears as though the cellular provider is changing its terms of service to give the company the right to share sensitive calling data with third parties.

At issue is so-called Customer Proprietary Network Information (CPNI) data. While CPNI data does not include explicit information identifying your name and address or your phone number, it does include data on the calls you make and receive, and the services that you may make use of. This includes information about the features of your phone and its capabilities. The data could easily be mined to see what kinds of businesses you call and how often.

Verizon Wireless has been contacting its customers via snail mail to inform them of their intent to share CPNI data with its "affiliates, agents and parent companies (including Vodafone) and their subsidiaries." The company says that customers who do not want their CPNI data shared need to call 1-800-333-9956 to "opt-out." Upon dialing the opt-out number, Verizon customers will be prompted for their phone number, billing ZIP code, and last four digits of their Social Security Numbers (in the case of businesses, their Employer ID numbers). Failure to opt-out will be interpreted by Verizon Wireless as "consent" to the company's data-sharing practices.

Although the Federal Communications Commission has said that it is very concerned about the protection of CPNI data, and is exploring the possibility of strengthening its rules on the issue, Verizon's opt-out notice appears to fulfill the Commission's CPNI disclosure requirements.

The Skydeck company blog was the first to suggest that what Verizon wants to do here is use CPNI data to offer targeted advertising. For its part, Verizon Wireless only says that it hope to improve its "services," but give no concrete examples of what such improvements would look like. Without a doubt, the notice given by the company is extremely vague. Skydeck has a scanned PDF copy available for your perusal.

Verizon Wireless may just be a first mover among other telcos. The race is on in the telecom industry to tap the well of advertising for mobile services, and this opt-out approach is guaranteed to give Verizon a lot of CPNI data to share, an undeniable treasure trove of information for marketers. We don't envision Verizon selling this data to third parties, using it instead to build its own analytic advertising system to capitalize on the targeting in-house. The company isn't likely to broadcast such plans until they are very close to fruition, however.

We will update this story when we hear back from Verizon about this new policy. In the meantime, if you're a VZW customer and don't want your CPNI data shared, you know the number to call.