More Kindle Numbers Speculation

Techcrunch claims to know how many kindles amazon has sold:

The Kindle is such a small part of Amazon’s overall business that the company does not break out how many it’s sold. But we found out anyway: 240,000 Kindles have been shipped since November, according to a source close to Amazon with direct knowledge of the numbers.

Two questions. How trustworthy is the source? And is that a good number or not?

The answer to the first is who knows, but it’s fun to speculate (but amazon not releasing an official number is getting boring). The answer to the second is ‘it depends’. 

I’ve got to admit that 240,000 is a bigger number than I expected, and getting close to a viable business. But it’s not bit enough to be a critical mass – that is, a number that shifts the expectations for readers and publishers so that ‘ebooks the kindle way’ signals some kind of paradigm shift. We’re still a long way from that