Some interesting info here for the statisticians amongst you
http://www.theregister.co.uk/2008/11/07/long_tail_debunked/Examining tens of millions of transactions from a large digital music provider, economist Will Page with Mblox founder Andrew Bud and Page's colleague Gary Eggleton, looked to see how large and valuable the "Tail" of digital music may be. They produced a spreadsheet with 1.5 million rows - so large, in fact, that it required a special upgrade to their Excel software (and more RAM) - and the three revealed their work at the Telco 2.0 conference this week.
They discovered that instead of following a Pareto or "power law" curve, as Anderson suggested, digital song sales follow a classic Log Normal distribution. 80 per cent of the digital inventory sold no copies at all - and the 'head' was far more concentrated than the economists expected.
In another surprise, 80 per cent of the revenue came from 52,000 songs. What's eye-catching about the number? Well, the typical inventory of a conventional high street record store was around 4,000 CDs. Or ... around 52,000 songs.
I remember berating the music industry some years ago for their hypocritical actions in on the one hand selling digital copies of music and on the other claiming that "pirates" where the cause of the local record store closing, I pointed out they couldn't have it both ways, these figures show quite clearly where anyone who was formerly operating a physical music based store should lay the blame, fairly and squarely on the shoulder of the music industry who made the physical market place what it is today, near dead.
