The widespread availability of third-party applications for Windows was one of major reasons for the Microsoft operating system’s rise to dominance decades ago. In that light, it’s interesting to see the company starting from scratch, in some ways, as it tries to build up a strong ecosystem of new apps for the Windows 8 interface in advance of the new operating system’s launch in late October.

As of last week, there were more than 2,000 apps available globally in the Windows Store, according to research by Wes Miller, an analyst who works for the independent Directions on Microsoft research firm.

As noted by Mary Jo Foley of ZDNet, these are new apps, previously known as “Metro-style,” built using the WinRT programming interface. Traditional desktop apps will also be listed in the Windows Store for separate download.

With less than a month to go before Windows 8′s release, Microsoft is rallying to boost the number of apps in the Windows Store. Over the weekend, Microsoft held an AppFest in India where participants set a new world record for the “Most Participants in a Software Development Marathon in One Location” — 2,567 developers coding for 18 hours straight.

And yesterday, Microsoft CEO Steve Ballmer was in San Francisco to talk up Windows 8 to developers and give them a fleeting glimpse of a Surface tablet. He underscored one of Microsoft’s major selling points, the sheer size of the market for Windows PCs — noting that hundreds of millions of PCs will be sold over the next year.

Wired’s Alexandra Chang describes his pitch as “almost a plea.”

“It’s all hands-on deck,” Ballmer said, according to the Wired piece. “I suspect I’ll spend more time in the Valley in the next month, two months, three months than at any time since before I dropped out of Stanford to go on out to Microsoft because there’s just so much that needs to be done.”

Reference to WinRT corrected since original post.