Changing your PC's hardware may interfere with the copy protection system.
Ubisoft has stated that the DRM system for Anno 2070 is working as intended, despite problems arising when users change their hardware configuration.
Earlier this week it was reported that changing your graphics card is apparently enough to confuse the game's DRM system.
But now Ubisoft has claimed that the Tages DRM is working exactly as it's supposed to:
"While it's correct that copies of Anno  include three activations and that changing hardware may trigger the need for reactivation, the vast majority of Anno customers never encounter this scenario," said Ubisoft, in a statement to RPS.
"On the rare occasion when a customer does need additional activations, Ubisoft customer service is available to quickly resolve the situation, and we encourage those customers to contact us directly so that we can ensure they are able to continue to enjoy their game."
Tages doesn't allow users to deactivate a given installation, opting instead to leave a configuration file on your PC when you choose to remove the game. In theory, this should allow you to reinstall the game at a later date without a hitch, but as RPS notes, this won't be the case if you've formatted your PC in the intervening period.
In short, if you're installing the game on multiple PCs and you make any alteration to your hardware setup, Tages is likely to give you grief.
This all seems pretty ridiculous to me, and I'd imagine it's the kind of thing that would discourage PC gamers from buying Ubisoft products. As RPS points out, this kind of hassle only affects legitimate users, as pirate games invariably just strip the DRM out. What kind of message does that send?