Ubuntu’s built-in Software Center, which allows users of the popular Linux distribution to purchase software, is attracting game developers. A recent partnership with the backers of the Humble Indie Bundle proved successful. Mainstream publishers like EA are also starting to take an interest. The Linux desktop may finally be achieving credibility as a target for commercial games.

The Humble Indie Bundle is a popular promotion that allows users to pay what they want for a selection of computer games created by independent developers. The games are cross-platform compatible and distributed without any DRM. The fifth bundle, which recently launched, attracted a considerable audience on the Linux desktop.

The organizers of the bundle partnered with Canonical to make the games easily available to participating Ubuntu users through the Ubuntu Software Center. According to an entry on the official Ubuntu application developer blog, the Ubuntu Software Center served the bundle to nearly 10,000 buyers within the first 72 hours after it launched.

The Humble Indie Bundle website, which publishes average purchase prices for users on each platform, indicates that Linux users voluntarily paid more than Mac and Windows users. According to the current statistics, the Linux average is $12.50 compared to the $7.97 average for Windows users.

These results aren’t unexpected—the Linux audience has shown similar generosity in previous iterations of the Humble Indie Bundle. Wolfire Games, which distributed its title Lugaru in the first bundle, found that Linux users contributed twice as much as Windows users on average. Almost a quarter of Wolfire’s revenue from the bundle came from Linux users.

There is clearly a healthy audience for commercial games on the Linux desktop, but the relatively small number of total users and the lack of an effective distribution channel for reaching them has historically deterred mainstream game developers from treating the platform as a first-class citizen.

Canonical’s efforts to turn the Ubuntu Software Center into a retail platform are helping to remedy this issue. Games like Braid, Oil Rush, and World of Goo have reportedly seen strong sales on Ubuntu and rank among the most popular paid applications in the Ubuntu Software Center. That success is helping to attract bigger publishers, such as EA, which recently added several of its HTML-based games to the Ubuntu Software Center lineup.

Linux gaming could soon get another major boost in the form of Steam support. Valve denied plans to bring Steam to Linux in 2010 when evidence surfaced that suggested the possibility of a port. Valve later embraced the opportunity that Linux presents, finally confirming to Linux hardware news site Phoronix in April that the Steam client and Source Engine are on the way. The latest news suggests that Steam could possibly even arrive this year.

Linux gamers have traditionally had to use Wine and similar binary compatibility layers to run Windows versions of games on the Linux operating system. The growing availability of native ports is welcome news for Linux enthusiasts who have hoped for acceptance from mainstream game publishers.

The popularity of these games also serves to illustrate the potential value of Canonical’s Software Center as a catalyst for attracting third-party commercial developers to the Linux platform. It’s not clear yet whether this success can be translated to other kinds of software, but it’s a promising sign that developers are starting to take notice of the Linux audience.