GM and Toyota parting ways on hybrids?

Rumor - and we must stress that it's an unsubstantiated one - has it that GM and Toyota will be parting ways on their hybrid development collaboration. Aw, and they never even got a chance to consummate the marriage by screwing each other over, which is what joint ventures do best. What's probably more important in the long term is that this split is said to also affect their hydrogen/fuel-cell technology sharing agreement, due to a disagreement in exactly how much information was to be shared. It's very tough to "read" this one - did one company have a clear advantage over the other, did corporate paranoia torpedo the deal before it ever took off, or was there just a philosophical difference on which path to take? Together, the two companies might have stood a better chance of making breakthroughs in the base technology, and also in convincing energy companies that this is a market that should be serviced.