Or do they include digital sales?

Should be retail only. VGChartz doesn't track digital sales.

Doesn't that make the numbers rather useless? Judging from Wii U owners I know, and the impressions I get on the web, downloading is fairly common, so the actual numbers could be way off what VGChartz has.

All you can really do is try to establish a baseline of how large a share of sales tend to be downloaded and apply a multiplier to games that are on the eShop. 10% more, 20% more? It varies by title, obviously, but it's better than assuming that nobody bought it on eShop.

The Wii U is actually probably the least affected by the lack of digital sales tracking.

People think the system sales are bad, but what about all the people who downloaded their Wii U's?

physical only until a way to track digital is conceived.

Well, judging by the sales of Nintendoland the WiiU probably is undertracked...

Considering how small the Wii U storage is, I don't see digital distribution really being big enough to make physical sales irrelevant. Physical is still the dominant format and it will be for a long, long time.

Considering this has been the case for every non-Nintendo handheld and console for several years now, I'm surprised it hasn't been brought up more.