Back in December last year, Steam began region locking PC games to prevent people from exploiting the low currency values in some nations. While the restrictions didn't affect the purchase of Steam keys, anyone who bought Steam gifts from regions such as Russia would only be able to activate the games if they lived in the same region.
This kind of region locking is reasonably easy to get around. Users quickly discovered that they could activate Steam gifts through a VPN to an appropriate region, and then play it without a VPN. But with Steam's new regional restrictions on game gifting, this will no longer be possible.
Now, Valve is stipulating that Steam gifts from some regions can only be activated and played in the regions that they were bought in. For those that are trying to buy extremely cheap games, this means using a VPN each and every time you want to play, which can be an unattractive option for multiplayer games in particular.
The restrictions, which have been applied retroactively to games gifted after December 2014, also affect those who actually live in cheap regions. People who are gifted games (or, in some cases, purchase games) in these regions won't be able to play them outside their country. So when a user goes on a holiday or moves internationally, access to their games is locked.
With currencies remaining weak in some regions such as Latin America and eastern Europe, it's no surprise that Valve is trying to cut down on people exploiting this fact. It's also not the first time we're seeing PC games region locked: select games, at the discretion of their publishers, have had regional activation restrictions for years.