For example, if someone owns Nike I can't say I am Nike Companions and sell shoes, even though Nike doesn't own the trademark "Nike Companions".
Another (more relevant) example, you can't take a trademark out on y.com, as much as yahoo wishes they could, because they don't (I don't think anyone can) own the trademark to the letter Y.
If you own the base trademark, it's probably a lot less important to go after the .com trademark too. Google, for example, apparently saw no need to trademark GOOGLE.COM - if anyone created a site curiously similar to google.com, presumably Google's attorneys would use their GOOGLE trademark to pursue the matter.
Even if you own the underlying trademark, though, it might be worth going after the .com name. Usually, trademarks are restricted to a particular area of endeaver. Hence, the same name is used as a trademark by many firms in different industries. If I had one of these rather limited trademarks and was lucky enough to own the .com domain, I might register the .com trademark too. (Even then, it's probably not absolutely necessary.)
Interestingly, some generic-word domain registered trademarks are listed as abandoned. These include cars.com, auto.com, and perfume.com. (No, that doesn't mean you can go out and trademark them. Cars.com shows a TM on their site, as does autos.com. And while perfume.com isn't specifically flagged with a TM, it looks like they have used it commercially since 1995. Check with your IP attorney before you get too excited. :))
CASELAW: A Top Level Domain (e.g. ".com") will be perceived as part of an Internet address and does not add source identifying significance to the composite mark. In this case, the board held that "PATENT & TRADEMARK SERVICES INC." is merely descriptive of the company's services and that the term "INC." merely indicates the type of entity that performs the services and carries no significance as a mark. Cf. In re Patent & Trademark Services Inc., 49 USPQ2d 1537 (TTAB 1998).Example: A registration application for the mark "WWW.ABC.COM" (an on-line clothing sales company) includes specimens of its trademark used in the form of an advertisement that states "visit us on the web at www.ABC.com." This application will be rejected for failure to identify the source of the goods or services; the "visit us on the web at" portion of the specimen serves only to identify the LOCATION of the store... not the SOURCE of the product or service.
[mycorporation.com...]
IV. DescriptivenessIf a proposed mark is composed of a merely descriptive term(s) combined with a TLD, the examining attorney should refuse registration under Trademark Act §2(e)(1), 15 U.S.C. §1052(e)(1), on the ground that the mark is merely descriptive. This applies to trademarks, service marks, collective marks and certification marks.
Example: The mark is SOFT.COM for facial tissues. The examining attorney must refuse registration under §2(e)(1).
Example: The mark is NATIONAL BOOK OUTLET.COM for retail book store services. The examining attorney must refuse registration under §2(e)(1).
The TLD will be perceived as part of an Internet address, and does not add source identifying significance to the composite mark. Cf. In re Page, 51 USPQ2d 1660 (TTAB 1999) (addition of a telephone prefix such as "800" or "888" to a descriptive term is insufficient, by itself, to render the mark inherently distinctive); In re Patent & Trademark Services Inc., 49 USPQ2d 1537 (TTAB 1998) (PATENT & TRADEMARK SERVICES INC. is merely descriptive of legal services in the field of intellectual property; the term "Inc." merely indicates the type of entity that performs the services and has no significance as a mark); In re The Paint Products Co., 8 USPQ2d 1863 (TTAB 1988) (PAINT PRODUCTS CO. is no more registrable as a trademark for goods emanating from a company that sells paint products than it would be as a service mark for retail paint store services offered by such a company); In re E.I. Kane, Inc., 221 USPQ 1203 (TTAB 1984) (OFFICE MOVERS, INC. incapable of functioning as a mark for moving services; addition of the term "Inc." does not add any trademark significance to matter sought to be registered). See also TMEP §1209.01(b)(12) regarding marks comprising in part "1-800," "888," or other telephone numbers.
V. Generic Refusals
If a mark is composed of a generic term(s) for applicant’s goods or services and a TLD, the examining attorney must refuse registration on the ground that the mark is generic and the TLD has no trademark significance. See TMEP §1209.01(b)(12) regarding marks comprised in part of "1-800" or other telephone numbers. Marks comprised of generic terms combined with TLDs are not eligible for registration on the Supplemental Register, or on the Principal Register under Trademark Act §2(f), 15 U.S.C. §1052(f). This applies to trademarks, service marks, collective marks and certification marks.
Example: TURKEY.COM for frozen turkeys is unregisterable on either the Principal or Supplemental Register.
Example: BANK.COM for banking services is unregisterable on either the Principal or Supplemental Register.
The examining attorney generally should not issue a refusal in an application for registration on the Principal Register on the ground that a mark is a generic name for the goods or services unless the applicant asserts that the mark has acquired distinctiveness under §2(f) of the Trademark Act, 15 U.S.C. §1052(f). Absent such a claim, the examining attorney should issue a refusal on the ground that the mark is merely descriptive of the goods or services under §2(e)(1), and provide an advisory statement that the matter sought to be registered appears to be a generic name for the goods or services. TMEP §1209.02.
[keytlaw.com...]