PARIS — One of the biggest changes in the history of the Internet could be set into motion Monday. Whether that is a good thing or a bad thing remains open to fierce debate.

At a meeting in Singapore, the Internet Corporation for Assigned Names and Numbers, which oversees the Internet address system, is expected to approve a vast expansion of the range of addresses available. The group wants to make it possible for Internet users to create their own extensions like .com, .net or .org.

So, get ready for Web sites that end with the names of cities or brands, like .berlin or .canon, to name just two entities that have expressed interest in the proposed system. Crafty entrepreneurs are busy thinking up sites like iwant.beer or whatsfor.dinner.

Icann envisions hundreds of new extensions, and that is just in the first round of applications. The overall range of Internet addresses on offer would increase exponentially.