The worlds of Trade Marks and Internet Domain Names have been the source of much confusion. Eventually it was decided that, in order to expand the range of names available, and presumably to reduce the dangers of trade mark infringement and passing off disputes, the range of domains would be extended.
Additional domains are now to become available such as .ltd and .info etc.
There are at least two ways of getting into trouble by virtue of the trading name chosen. First, if the name is already a registered Trade Mark, then use will be an infringement of that mark. Second is the tort of passing off. When I trade on the goodwill achieved by somebody else in their name or title, this is a wrong irrespective of the registration of any mark. Nor is the use of one, any less passing off than it would be to use the other.