Making a game for PC or Mac? You'll probably want access to Steam's 75 million subscribers and their often joked-about spending problem. After all it turns out most people are buying games on Steam that they never even install! Now there's a market you want to tap into!
Steam's almost-monopoly causes some real problems, with gamers often refusing to buy games from you directly, saying "I'd buy it if it was on Steam". A couple of years ago it was basically impossible as an indie dev to get onto Steam. Even with the launch of Greenlight, their crowdsourced vetting service, it was extremely difficult as recently as last September. Fortunately in January Valve started ramping up the number of games they were Greenlighting and right now they are accepting a batch of 75 games every two weeks. Lets ignore for now what this rash of games is going to do for your game's release (hint: find an audience outside Steam) and instead address the question 'How hard is it to get through Greenlight in 2014?'.