Due diligence is a two-way street, according to Reid Hoffman. In an episode of the "Possible" podcast released on Wednesday, the LinkedIn cofounder said he always asks founders to look into his background before letting him invest in their companies."I say: 'Look, I'm going to give you a bunch of references. I would like you to find anybody that I perfectly worked with,'" he said. "You're allowed to talk to anyone and you can tell them, they know this, that they should tell you my strengths and weaknesses. ...