It's no secret that Blizzard plans to make money off user-generated content uploaded to StarCraft II's Marketplace. As stated earlier, authors providing premium content will get a percentage of the final sale. However, according to a gamesindustry.biz interview with Blizzard CEO Paul Sams, the company isn't quite sure how it's going to work just yet, or how gamers will interact with that system.
But what Sams did reveal was that Battle.net will not become another Steam: the company doesn't plan on opening its borders to other developers and publishers. "I think at the moment our focus is squarely on Blizzard products and we need to make sure that what we're doing is right for our games," he explained. "It's also a big differentiator for us. There's really not a lot of companies out there that can or are willing to do this because it's a huge expense."
It's quite possible that Blizzard could use the same system provided by Xbox Live and the PlayStation Network: gamers purchase "points" using a credit card or gift card. Thus, a StarCraft II fan could purchase a new premium map for 800 Blizzard Points... or use some other monetary system using a nifty Blizzard-related name.
"We can only say so much right now, but the plans are much bigger, much grander... and have long-term positive implications for gamers," he added, referring to Battle.net posing as more than just a free match-making service. His entire interview with gamesindustry.biz is located here.