The change approved by Icann, which manages the domain names system, means the range of possible domain names can be massively expanded beyond existing choices such as .com and .co.uk.
Companies will be free to apply for domain names consisting of any combination of letters, such as .hotel or .nyc or .London, in what has been likened to a new gold rush on the internet.
Jonathan Robinson, the chief operating officer of NetNames, claims this will raise complex questions for marketers and trademark owners, both about whether to take pre-emptive action against cybersquatters and how new domains affect search optimisation.
Robinson said: "It can be argued that the expansion of available suffixes is the equivalent of opening a can of worms in terms of online infringement and cybersquatting.
"It seems logical to assume that as domain numbers increase, so too will the levels of speculative activity."
"Brand owners may find themselves in the position of having to register numerous new domains to protect themselves but, with varying fee estimates, that could well turn out to be an untenable marketing expense for some. Nonetheless, the impact on existing domains remains to be seen.
"In the case of a big brand, presumably any browsers visiting a newly registered domain would be redirected to the original top level domain in any case. There will also be question marks over how new domains will affect search optimisation and consequent site traffic and PPC advertising rates.
"One thing that does seem clear is, with the final pricing and potential refund and dispute procedures not yet in place for applicants, brand owners and the trademark community will be keeping an extremely close eye on developments in the coming months."