While the early adopters flock to Google+ and our kids and moms become power-users on Facebook, LinkedIn is where business gets done. Execs from all Fortune 500 companies are there, and 59 percent of those active on social networking sites say LinkedIn is their platform of choice over Facebook or Twitter, up from 41 percent who called LinkedIn their most important social account a year earlier, according to a June report by Performics and ROI Research.