In an interview at the Game Developer's Conference, Valve Software's vice president of marketing, Doug Lombardi, told Toms Games the company is considering adding music and video content to its Steam digital distribution platform.

After a rocky start back in 2002, Steam has gone from strength to strength, with record sales for the holiday period last year--a 158 per cent increase compared with 2006--and now has over 15 million members.

When asked if he was surprised by the sales numbers, Lombardi responded: "We were very surprised. The numbers for those [third party] titles (BioShock, Call of Duty 4) in particular blew us away. It was a great year for PC games. I don't think that any publisher that's released a game on Steam hasn't come back to it with another title."

Lombardi went on to say the company wants to add more content to Steam. "We're looking at more casual games and international games. And we're also looking at other types of content like video and music. We're definitely having those conversations and meetings, and we're reaching out to folks with other types of digital entertainment. I think before the end of the year, you'll probably see some pilot programs with other digital entertainment on Steam."

Tom's Games also asked how sales of the Orange Box on PC compared with its release on Xbox 360 and PlayStation 3, to which Lombardi replied that PC sales were strong, "at least a two-digit percentage increase over the console sales."

As for what Valve is working on next, its subsidiary Turtle Rock Studios has Left 4 Dead due in May, and Valve is hard at work on Half-Life 2 Episode Three. Beyond that?

"We're in the mode now of asking ourselves what's the next Portal project? Where does Gordon go next?" said Lombardi. "So we're probably going to go away for a while, as Valve does, and work on those things. But we're definitely going to have more Portal and Half-Life 2 coming."

Read the full interview over at Tom's Games.