The big point about corporate ownership of media is that the news is slanted toward the interest of the corporate parent and corporations in general. If that were the case, I would think that we would see instances of negative spin applied to corporate rivals more often than we are. News agencies aren't the only ones supposedly under the gun. I recall a scene from Bob Roberts of a Saturday Night Live-like show that was afraid to put an anti-nuke sketch out of fear of offending their nuke building corporate parent.
An angle that is making itself felt is where corporations, and their media properties, are looking at the consequences of pissing off government regulators over a story. AOL/Time Warner is facing that decision now regarding the Plame scandal and upcoming mergers. I have always believed that corporate influences on government are less extensive than hyped. The power has always been the other way around, any company can find itself regulated into oblivion.
A respected, lightly monitored media outlet is a good possession for a corporation. If this direction were to continue, however, no corporation would be willing to risk light monitoring. Forget government lawyers, it will be the corporate lawyers, in a fit of CYA, that will be doing the dirty work.