Net users who mistype the name of a .com or .net website into their browser may no longer get an error message.
You might have met this page for the first time this week
Instead they may see a special page prepared by .com and .net overseer Verisign that lists possible alternatives and paid for suggestions.
But the move has won protests from many other net firms who say Verisign is hijacking their customers and is inadvertently helping spammers spread their unwanted wares.
One net organisation has written software that blocks the site finding system and another has filed a lawsuit to get the service shut down.
Every day more than 20m net users mistype the name of the .com or .net domain they want to visit.
Although domains are searched for with words, computers know them better as numbers. Your machine consults lists of which domains are where on the web whenever you go browsing online.
Before Monday if the mistyped domain name did not exist, users would have seen an error message telling them as much.
But now mistyped domain requests are being redirected to a Site Finder service set up by Verisign that lists the sites it thinks someone might be looking for.
The Site Finder system has brought protests from other net firms, such as AOL and MSN, who say Verisign could hijack searches by their users.
Verisign holds the master list of who owns which .com and .net domain so anyone looking for websites using these domains must consult its records.
Other web users fear that the move could aid spammers.
Many senders of unwanted commercial e-mail messages use non-existent web domains to help hide the origins of their traffic.
Some anti-spam organisations block all mail that originates at non-existent domains but Verisign's creation of Site Finder makes this impossible.
In retaliation the Internet Software Consortium (ISC) has written software that blocks Site Finder and produces the old style error message.
The non-profit ISC makes the BIND program which is used by many organisations to look up the domains that people want to visit.
Verisign is also facing legal action over the creation of Site Finder.
Popular Enterprises LLC, which owns the netster.com search site, alleges that Verisign is engaging in unfair practices with the creation of Site Finder.
The lawsuit is seeking to have Verisign's system shut down.