Credibility Cards

It's my word versus yours. He said/she said. Hear say. When it comes to trial by media, the "who" matters more than the "what". Take rape for example. Ex-IMF director Dominique Strauss-Kahn had been brought up on charges for allegedly chasing a maid down a hotel hallway, then sexually assaulting her. Quite a strong, and specific, accusation. The case has been thrown out by US prosecutors, citing the accuser lacks credibility. Not a lack of evidence, a lack of credibility. The accusation may be true, but the source, the accuser, lacks credibility. What exactly is this "credibility", and where can I get some?
Ben Stein views occupation as the source of credibility. Responding to the Strauss-Kahn accusation, he stated:

... I have had hotel maids that were complete lunatics, stealing airline tickets from me, stealing money from me, throwing away important papers, stealing medications from me. How do we know that this woman's word was good enough to put Mr. Strauss-Kahn straight into a horrific jail?

It's not the first time a lack of credibility has derailed an investigation. When three Duke Lacrosse players were accused of gang-raping a woman, the case was dismissed before it could make it to trial because of the accuser lacked credibility. The narrative covered by the media put the Duke players as the focus, while the alleged victim remained a nameless and faceless stripper/escort who kept changing her story. What was her story again? It doesn't matter now, if it didn't matter then.
Dominique Strauss-Kahn and the Duke Lacrosse players, like others, may have been the victim of a false accusation. The question is, what exactly gave them credibility over their accusers? Legally, the slew of previous accusations in "The Great Seducer" Strauss-Kahn's wake would be inadmissible as relevant evidence in a trial, yet the victims past behavior is enough for a case dismissal pre-trial. The same thing happened with the Duke Lacrosse case. Admitting to hiring and having sex with the accuser apparently did little damage to the players' credibility.
Justice may be blind, but she see's your credibility. When it come's to he said/she said, never mind what is said by either party or the law, instead focus on the he/she. Without credibility, you have no case. You know, justice.