Newest episode of Venture Voice is an interview with the founder of LinkedIn. I found most interesting the discussion on what I feel is the biggest problem to the legitimacy of LinkedIn: Mediocre workers with glowing testimonials bringing down the value of a referral by mis-using the networking concept.
It goes into some interesting ideas on how they plan to handle it in the future and how they intend for it to be handled today if people utilize the tool properly.
(If you don't want to listen to the whole thing, this part starts around the 33 minute mark).
Venture Voice #40: Reid Hoffman of LinkedIn