Google's own statements on it pretty much boil down to globals having an advantage out the gate, but after a period of being established, everyone settles onto pretty much equal footing with content quality being the prime driver in rankings. The specifics of the time frames are unstated.
Google has apparently done some work on transcribing (to text) technology for video, whether and to what extent that is deployed remains unknown, although empirically this seems to be still in development. This opens up some interesting possibilities, either now or in the future.
It does seem that Google has a pretty strong association on some level with TV and television, which can be seen on default adsense choices before the domain is analyzed by the spiders. Will be interesting to see if they lean towards weighing video content on TV sites more heavily in the future.
Yahoo seems to be much more tied to exact keyword value, although there seems to be some bias towards globals. However this seems to be slightly biased towards the global tlds, or maybe this is due to the amount of sites present in competition. Not tested. If this is the case, I wouldn't be surprised if Yahoo is treating TV as a global in this regard.
If you are holding TVs and not ready to develop fully yet, it might be worth considering setting up a "placeholder" site. As google gets more sophisticated, domain age could well be counted from the point of site activity rather than the initial registration point. This is pure speculation, but would not be unsurprising. Anyone's guess, but I think it might be worth it if you are planning a long range hold for strategic reasons.
At this point, if you are optimizing and have a fairly new site, their might be advantages to optimizing towards Yahoo or Bing. Google optimization is probably possible, but the cat isn't out of the bag on that one yet, could be a tough climb for at least the first year or two.
Of interest is that the webmasters tools feedback area has a fair amount of support for full selection of targeting regardless of the extension. The argument being that companies may be primarily doing business in areas that are outside of their native regions, or at least in different regions than their servers. Tough call on how that will play out, but it could open the door for some interesting shakeups down the road.
All in all, Google's long term plans remain a mystery. The only known is that it will continue to evolve in sophistication. Short range strategies may vary considerably from midterm to longterm strategies.
The web is an evolving system, all we can do as domainers is watch the trends and place our bets.
