"I take it as meaning that MS is going to implement IE10 with as much low level integration to the OS as possible, i.e. it can make efficiencies by not having to support multiple platforms."

Then what they need to say, if they can prove it, is something more like "IE is faster than Chrome." If they're doing that at the expense of being single-platform, that's a tradeoff, not a feature to announce.

And if being single-platform doesn't make them faster than Chrome, what does this announcement mean? "Despite making this tradeoff, we are still bested."