Although australia.internet.com has, apparently, persuaded some jusrisdictions to trademark <internet.com>, a court challenge to the validity of such a registration in any Berne convention would, in my opinion, rule the mark invalid on the ground that internet.com as applied to an Internet-related business is purely generic and, thus, incapable of trademark protection.
It is, of course, notable that even Australia won't trademark the domain!!!
This is the sound registration principle applied in most industrialized nations. If, however, australia.internet.com were ever to argue that <internet.com> had acquired "secondary meaning" (that is, that consumers associated the domain name exclusively with its company), I think that trademark law would have to adapt to legislate, by statute, that second level generic terms are not capable of trademark protection as applied to goods and services related to the generic term.
Australia.internet.com should be happy enough that they will receive type-in traffic and leave the trademark argument alone. Just as Barnes & Noble benefits from <book.com> and <books.com> type-in traffic without claiming secondary meaning in those generic terms, so, too, should the Aussie outfit be satisfied with the generic type-in traffic it receives. It is NOT entitled to trademark protection for Internet.com.
