I'd be very curious to know how much of Time Warner's DVD/digital distribution is through Amazon. That's probably the most relevant metric for measuring Amazon's leverage.
Admittedly this is a crude metric, but Amazon's market cap [1] is about 3x that of Time Warner [2].
[1] https://www.google.com/finance?q=NASDAQ%3AAMZN&ei=wWeYU_CtKs... [2] https://www.google.com/finance?q=NYSE%3ATWX&ei=sWeYU_CkLcea6...