Last week, customers of Verizon's ISPs in Illinois, Indiana, Michigan, and Wisconsin learned of an interesting alteration to their Internet service: The company is experimenting with what it's calling an "Advanced Web Search" page, which its DNS servers will distribute in response to non-resolvable or perhaps malformed URLs.

Instead of the typical error message a DNS server provides, Verizon's new page would offer users assistance for perhaps getting the URL they're actually looking for. It's a service not unlike one offered by regional phone companies to land-line users, which can interrupt "out-of-service" messages and ask users if they'd like to speak to an operator.

The potential to steer any DNS traffic in a different direction has some customers pondering whether Verizon or other DNS-providing ISPs have designs on filtering traffic, or at least offering customers the option to have traffic filtered for them.

Today, a similar service exists in the form of OpenDNS, a system of servers operating through a pair of DNS addresses that can not only offer to resolve malformed URLs, but to filter out calls to sites known to display explicit or objectionable content. It's a software-less service and it's free to users, though it makes money by selling advertising alongside its substitutes for error messages.

If Verizon is exploring malformed URLs as a revenue center, rather than charge customers, it could also be testing just how many page views all malformed URLs combined may register. Imagine "Oops" as a portal, and you get the idea of Verizon's potential alternate plan.

Verizon customers may selectively opt out of its AWS service, but as one Broadband Reports reader and Verizon customer discovered, opting out meant opting into something unexpected.

After opting out, he found a cookie installed on his system that would prompt malformed URLs to trigger his Web browser to display the "Page not found" resource screen from Internet Explorer 7. Which was all quite interesting, because he found it using Firefox. There's no word yet on opt-out behavior for Linux or Mac OS X customers.