The scope of a trademark search should be broad enough to include references to federal trademark registrations, state trademark registrations, and common law trademark rights. The federal and state register searches should also include pending applications, abandoned applications, and expired registrations. The reason for such a broad search is that trademark rights in the United States are granted on use, and registration is not required for rights to exist in a trademark (see BitLaw's discussion on common law trademarks). Thus, although pending applications and abandoned registrations indicate that no federal rights currently exist in those marks, the marks that were the subject of these applications could still be in use.
It is also important to discover common law trademarks even where no applications were ever filed to register those marks. Databases have been created that contain listings of product names, although they are not complete. Additional sources of data should be examined as well, such as periodicals which cover the area in which the trademark will be used, press releases, Internet domain name registrations, phone book databases, and corporate information databases. Trademark searches that do not contain a fairly comprehensive common law trademark search are of little value when determining whether to utilize a new mark.
Performing a search
Trademark searches are often performed by trademark searching companies, such as Thomson & Thomson, or by individual trademark attorneys. It is possible to perform a trademark search yourself, at no cost, although the results will not be on the same level as professional services. You can search for federal trademark registrations and applications at the Trademark Electronic Search System (TESS). Common law trademark searching can be accomplished, at least at a rudimentary level, through general search engines such as Google or Bing.
Limitations on trademark searches
Trademark searches are never "perfect" since they rely on databases which by the very nature of trademark law can never be fully up-to-date or broad enough. Since trademark rights can begin by filing an intent to use trademark application, it is always possible that rights have been established since the database being searched was last updated. In addition, since no registration is necessary to establish common law trademark rights, one can never be assured that all relevant common law marks exists in any of the available databases. Nonetheless, trademark searches are common and necessary, since experience has shown that in large majority of cases they successfully predict which marks are available and which are not.
Once the trademark search is completed, it is often helpful to employ a trademark attorney to give an availability opinion based upon the search. The retained attorney will review the trademark search and, based upon their experience, give a legal opinion as to whether your mark is available for use and for registration.
Given the nature of trademark searches (see above) and of the legal profession in general, the trademark availability opinion will include many caveats regarding the reliability of the opinion. However, the opinion is still valuable in that it contains the opinion of an experienced trademark professional who has evaluated many searches before. The use of trademark searches and availability opinions is standard practice for practically every major company before the introduction of a new trademark.
To determine whether the trademark is available for use and registration, the trademark attorney will examine whether any of the marks revealed in the search are likely to cause confusion with the proposed mark. In other words, the attorney will try to determine whether relevant consumers would be likely to associate the goods or services of one party with those of the other party as a result of the use of the marks. The principal factors to be considered in reaching this decision are the similarity of the marks and the commercial relationship between the goods and services identified by the marks. To find a conflict, the marks need not be identical, and the goods and services do not have to be the same.