Odds are, you have Steam installed.
If not, you might have at least one of another handful: Origin, Uplay, Desura, Battle.net (Blizzard), Glyph (Trion Worlds), or Capsule (GMG). In an era where 92% of PC game sales are digital, it’s increasingly important for companies to get involved in digital distribution and game management.
Looking to jump into the ring is Razer with its new platform, Cortex.