You can purchase games directly through the steam store and store them as a soft copy in your system, hence eliminating the requirement of a physical disk. Steam is a great way to purchase and organize your game library. Here is how to fix steamui.dll and steam not opening error on Windows 10. You can chat with other players, add them as friends, give/receive games as a gift, share your library, create groups, like and share screenshots of games, get achievements, collect collectible cards, use emoticons, stream gameplay and much more. In addition, Steam has a good social component which makes the service a kind of a social media platform for gamers.
The service itself is owned by Valve and was originally developed to distribute games of the same company, but in the near future, it made its platform open, where each developer could enlist their own games.
In the future, movies and music may also appear which will be a delight for all the steam fans. Steam is an online store of games and programs.