The role that Valve played in the evolution of Steam extends far beyond the simple activity of game distribution; it has fundamentally redefined how games are accessed and played by a global population of gamers.
From an initial service of delivering patches back in 2003, Steam has grown into something of a digital distribution leviathan. Innovation has been strategic on the part of Valve.
One of the major strategies used by Valve was the incorporation of the Digital Rights Management (DRM) tool, which was highly criticized for binding the user to the Steam service but was very important for ensuring software protection from piracy, which also kept the development environment safe and secure.
Another decision by Valve, to open up Steam to third-party developers in 2005, further democratized the platform, transforming it into some sort of mega-mart of all types of gaming content.
Such expansions not only increased the range of games available but also solidified Steam's place as a very important service to gamers and developers. Not everything was rainbows for Valve in its journey along the path of Steam.
The backlash was received at the beginning from third-party-intolerant gamers. However, the experience and explicit features of Steam built trust in it over time.
As much as forces change and react to dynamic factors, that is how much the very many efforts put in by Valve keep Steam significantly placed in the re-ordering world of PC gaming.