If at first you don't succeed, skydiving might be a bad hobby for you. Online retailing, however, you can try and try again.

After years of misery in the online realm, Wal-Mart (NYSE: WMT) is finally scoring an Internet hit with digital movie service Vudu. According to market analyst firm IHS, Vudu has quintupled its market share under Wal-Mart's stewardship to 5.3% -- in just 12 months' time. In the process, Vudu leapfrogged similar rent-or-buy services from Amazon.com (Nasdaq: AMZN) and Sony (NYSE: SNE).

Wal-Mart's jump from fifth place to third is all the more impressive because the company doesn't plug the service into a hardware platform all its own. Far-and-away leader Apple (Nasdaq: AAPL) leans on the iUniverse of gadgets to complement its iTunes music and movie store. Second-place Microsoft (Nasdaq: MSFT) attached its Zune Video Marketplace to the red-hot Xbox 360 and Kinect console. Sony did the same with its PlayStation 3. In fifth place, Amazon is slugging it out hardware-less, just like Wal-Mart -- at least until the company unleashes its long-rumored Android tablet.

Instead, Wal-Mart has ripped a page out of the Netflix (Nasdaq: NFLX) playbook by sliding its software into Blu-ray players, connected TV sets, and other entertainment devices made by other companies (and often sold at Wal-Mart, natch). The strategy seems to work in this nascent era of digital infotainment.

So why isn't Netflix on that top-five list? Well, this study looks at Internet pay-per-view video services, a market that added up to $229 million of total revenue in the first half of 2011. Do the math on Wal-Mart's share, and you get $11 million or so, a mere drop in the bucket for the retail champion. By contrast, Netflix collected $1.5 billion in first-half revenue on its subscription model, totally dwarfing the pay-per-view industry. The company plays in a whole different industry, where the only credible competition today comes from Amazon's Prime subscription service. Apples and pomegranates, my friend.

That said, Wal-Mart seems to want more of this online success. The company recently expanded its online-order, local-pickup program to all 3,600 stores, and has started testing an online grocery-delivery service reminiscent of Webvan and Amazon Fresh. But the online music service has gone to the Great Gig in the Sky. Wal-Mart is picking its battles.

Can Wal-Mart build on this success, or is Vudu an online fluke? Add Wal-Mart to your watchlist to keep an eye on the Arkansas giant. Whichever way the online venture goes, you'll be the first to know.