Ukie is trying to start collecting digital sales data for UK :

http://www.gamasutra.com/view/news/193127/UKIE_wants_your_video_game_sales_data.php

So, more tracability next gen ?

Would be a start

Finally, something tangible!

would be really awesome! but i would be more interested to see that for germany because pc gaming is big here and a lot of it is digital with steam and so on...

Nothern Europe might have peculiars numbers too.

One thing, BTW, won't it become necessary to dissociate free to play and classic business model ?

Awesome sauce

how will they manage to do so?

only PC games right now

Very ambitious. I do hope they can get more groups on board. More data is good data.

Actually outside of Steam deals and huge sellers (Diablo 3, Starcraft 2 etc.) don't expect much to change on a weekly scale.

http://www.biu-online.de/de/fakten/marktzahlen/datentraeger-und-downloads/alle-plattformen-im-vergleich.html

Most PC sales come from budget priced games and indie games.
A top seller list would become meaningless quickly when there's one HumbleBundle on sale for example and at the same time a PC version of a popular multiplat game is released but only found on place #6.
So the future top seller list would need to be sorted by revenue and then the HB games wouldn't appear either (just as they don't appear right now).

Furthermore:
http://www.biu-online.de/de/fakten/marktzahlen/datentraeger-und-downloads/distribution.html

38% of all games in Germany are sold digitally, but they only represent 11% of the revenue.

Another thing:
http://www.biu-online.de/de/fakten/marktzahlen/die-deutsche-gamesbranche-2012.html

1.5bn Euro revenue from games, 11% of them are digital, so 165m Euro revenue.
PC gaming brought it 464m Euro revenue, so AT BEST 36% of all PC gaming revenue is from digital sales.