Google Chrome OS - does it matter ?

This came as a shocking news to me today. Google has made a very significant move against the MS vs Google war with the announcement of Google Chrome OS. Specualtions of a Google OS has been in the wild for a long time. Two questions that came to my mind after reading this news was
1. why now ?
2. why netbook / browser centric ?

why now ?
Maybe there are playing tit for tat with MS. You Bing, I Chrome. With Bing hitting headlines and possibly stealing some of precious Google search shares, how do you counter attack and keep your publicity ratings high ? As long as I remember, this is the first time that the otherwise secretive Google has broken news on their vision for a netbook / browser centric OS. Probably Bing has forced Google Chrome OS to go on air.

why netbook / browser centric ?
Interestingly, netbook sales have been up during this recession. I was thinking that GOOG wants to target those sectors where it stands a chance. Converting desktop WIN users to a new OS will drain any company.Netbook is modeled to target customers who needs a computer for mail, chat, photos and the like. so positioning in this market should give GOOG a better shot.
Android -> mobile and other portable devices.
Chrome OS -> cloud computers.
Looks like the strategy is to break pawn chains, kill the bishop and rook before targeting the King.
Everyone knows that Google loves the cloud and intErnet. Browser based OS is a right choice for their philosophy to get things done in the cloud.

This is probably just the beginning of the battle. Google Chrome OS does definitely matter and it'll hold a spot in history