One of the first professional social networks ever founded, Toolbox.com, which serves IT professionals, has been acquired from the Corporate Executive Board by tech publisher Ziff Davis, Inc., the companies announced Tuesday. Founded in 1998, Toolbox.com blazed a trail for professional social networks (and social networks in general) by connecting IT professionals to enable them to consult with peers and experts, evaluate vendors, and plan and manage projects; like other professional networks, it is also handy for finding jobs and poaching, er, recruiting new talent. The network currently boasts 2.3 million registered members.