The big news this week at Google is that one of its highest profile and longest reigning employees left to go lead a competitor, Yahoo!. While Yahoo is ostensibly gone from Search, it is still playing in the Maps, Location, Email/Calendar, news aggregation, Mobile, and many others in the same fields as Google. Make no mistake…Yahoo and Google are competitors.

The choice of candidate for Yahoo is as good as it could have gotten (and much better than most envisioned in Ross Levensohn), and it seems like a stellar selection considering the Yahoo Board’s last few choices.

As Mayer told Charlie Rose in 2009, she puts an extremely high price on the value of the people at a company and after having been at Google for 12+ years, that is where most of the good people she knows now work. Google’s employees are also aware that Yahoo is going to be spend a lot of money on talent changes as Mayer starts her tenure tomorrow, so those not happy at their current situation know where to call.

Google has been in a fight over recent years to retain talent from employees that head to Apple, Facebook, or Twitter. But, I think this is a different league of problem that will reach high into Google’s Org chart.

I also think Yahoo is still screwed.