Online retail is big business and the market still has a lot of potential growth in it. Brick-and-mortar retail giant Walmart knows this, of course, but so far its online foray hasn't been as successful as it hoped. In a move that is meant to allow Walmart.com to better tackle the likes of Amazon and increasingly eBay, which has been pushing hard in the online retail sector as well, the company has announced it will add one million new items to its virtual shelves coming from third-party partners.

"We've added nearly one million new items to our online assortment with the introduction of Walmart Marketplace, making it even easier for customers to find more of what they want when shopping Walmart.com," said Kerry Cooper, Walmart.com's chief marketing officer. "Working with select retailers, known for their strong customer service and large online assortments of new merchandise, gives our customer more reasons to choose Walmart.com when shopping online."

The announcement comes with the launch of the Walmart Marketplace, a new partnership program to allow outside parties to sell through Walmart's online store. For starters, the retail giant will feature items from CSN Stores, which brings toys, home, baby, sporting goods and shoes, eBags, to provide bags and luggage, and Pro Team, which sells sports apparel and collectibles. The company plans to introduce additional partners over the next year.

Introducing third-party partners has been a great move for Amazon, currently the largest online retailer in the US, with the additional businesses moving $4 billion to $6 billion in merchandise value yearly. Amazon actually has millions of third-party businesses using the online store thanks to the simple and straightforward tools made available to them. Walmart is taking a different approach for the time being only partnering with a small number of established players. But, while Walmart is way behind Amazon in the online sector, eBay will probably feel the grunt of the expansion as it is also just starting to move towards being an online retailer rather than an auctions site and has managed to secure several third-party partners.