Some games contain icons or links that if clicked will open a web browser for the player to the company or games social media page. Some of the social media links that will regularly appear in games is Facebook and Twitter.
These typically appear in free-to-play or mobile games, but also appear in other PC games. Some games will also list social media network links for individuals who worked on the game rather than the company, such as the game Threes!
This features differs from concepts like Facebook Connectivity as it does not offer any kind of connecting to a social media service, just a link to them.