I looked up the application documentation. The UPSTO initially rejected it for the pricipal register because it was descriptive. DomainTools.com then disputed that and provided documentation that they say showed "domaintools" was used exclusively by them. However, they provided a goodle search of "domaintools" and my site came up sandwiched between DomainTools.com and the DomainTools.com twitter page (22-Aug-2011 letter, page 3). Then they claimed they used the term exclusively when their own submission to the USPTO shows that is not the case.