LinkedIn is set to go public this Thursday. The company has done a solid job establishing itself as the preeminent professional social network. It has balanced its revenues across jobs listings, services for HR departments and recruiters, and advertising. Its efforts in news filtering are unproven, as are its efforts to expand into platform APIs, but LinkedIn has a good chance to play a big role in identity management and authorization. It faces competitors like Hashable, whose professional contacts management feels a bit more modern to Matthew Ingram, and career sites like BranchOut that are building off of Facebook’s platform. With an IPO this week, I guess that rules it out as a near-term takeover target for Google or Facebook.