There’s been a bit of discussion in the comments sections of certain Game|Life posts about why we don’t use the sales-tracking website ******** for any serious discussion of game industry business, but Gamasutra’s Simon Carless has explained all of the site’s problems in detail.
In short, Carless verifies that ******** numbers are based mostly on rough guesses, not hard data. He points to the site’s treatment of Iron Man for the PlayStation 2, which VG Chartz had pegged at 53,000 copies — until NPD’s data came out with the game selling 130,000 copies. VG Chartz then edited its entry to a number closer to the NPD figure.
The site’s founder even admits to Carless that VG Chartz’ Metal Gear Solid 4 European sales numbers, which it breathlessly reported as hard fact in press releases to media outlets including Wired.com, were entirely invented: "It was based on first day Japan sales, first day America sales, and from that projecting for Europe / others which we didn’t get direct day 1 for."
As Carless summarizes, smart people projecting sales using all the publicly-available data is an interesting experiment, but the fact that other news outlets like the New York Times, Fortune, and Forbes are reporting these numbers as hard data is not a good thing.