Much like how technically the number of applications in the Marketplace doesn't really matter (though you can glean some info from it), how well Microsoft did or did not do on Monday, in terms of raw sales, seems to be a moot a point in the long run. Unless of course you're looking to ask rhetorical questions for major publications. Such was the case yesterday where lots of headlines were phrased "Was the launch a bust?" "Did it underwhelm?" "Is it really a huge success?" etc.
Fact is, we don't know, they don't know and no one will know for awhile. This is understood by everyone. Citing anonymous sources who claim to know that "40,000" devices were sold was passed around as evidence, trumpeting headlines despite not knowing the authenticity of the claim. It's the equivalent of journalist trolling (the use of "?" is always a sure sign). Sure, there were very few lines if any. Sure it was a Monday (launches do better on Fridays) and we now know that stock was quite low (here and here), not even lasting the day at a lot of AT&T and T-Mobile stores (we heard reports of anywhere from 2 to 12 Samsung Focuses per retail outlet).
Did anyone really expect iPhone like masses to appear? No. The only thing to consider is that Microsoft is in this for the long run. This is day #1 of what will be a multi-year process. Two things to remember about Microsoft: they have lots of money and they are suborn when committed to entering a market. Lets revisit this six months from now where adoption rates will be better understood, where the OS has had a chance to build public awareness and real figures make their rounds, shall we? Yes, it's fun to speculate, but everyone in this business knows one day tells you very little e.g. the Palm Pre sold very well for Sprint its first day, fast forward one year and they're sold to HP.
But instead of going further, I could just refer you to Devindra Hardawar's piece at MobileBeat which does a much better job of making these points.