Publishers who use Steam now have the ability to block cross-region game gifting – at least in Eastern Europe and South America were games are sometimes significantly cheaper.
The discovery was made by NeoGAF user JaseC who found that Konami had disabled the ability to gift Metal Gear Rising: Revengeance to players in other territories.
Under the game's Steam directory a new tag titled 'AllowCrossRegionTradingAndGifting' was set to 'No'.
It seems that for now at least this feature does not affect retail keys and while it is limited to specific regions at this time there's every possibility it will expand over time. Currently, it's unknown if other publishers are availing of the feature.
Valve has not yet issued a statement on the new restrictions.