"Through its recent acquisitions, Alibaba.com is building the world's first global e-commerce supply chain."

You might read a similar sentence in any e-commerce company's press release, any day of the week. But when Alibaba.com announced its latest move to create a Chinese business-to-business empire, it wasn't just whistling Dixie.

Late last night, Alibaba.com -- successful scion of Hong Kong-listed Alibaba Group -- announced that it is buying e-commerce facilitator Auctiva. When a small business wants to sell merchandise on Amazon.com (Nasdaq: AMZN) or eBay (Nasdaq: EBAY), or even open an independent storefront somewhere on the Internet, Auctiva lends a helping hand. It offers tools for listing items for sale, and for marketing and managing inventory. It hosts images shown to shoppers, and even hosts entire storefronts itself. According to Auctiva, it's provided such services to some 1.5 million sellers on eBay alone over the past dozen or so years, and it's personally responsible for helping sellers list more than 4 million items for sale every month.

In short, Alibaba's purchase of Auctiva is even more important as its purchase of Vendio was two months ago. Auctiva currently boasts more than 170,000 "active users" of its services; for Alibaba, this purchase captures a merchant audience twice as big as the Vendio deal did. Combined, Alibaba now controls the connection of a quarter-million American merchants to potential suppliers in China and elsewhere.

Who's it hurt?
In an announcement just 10 paragraphs long, Alibaba took time to fire a shot across the bow of companies that have, to date, counted many of these merchants as its own -- firms that hawk liquidated and overstocked merchandise to online merchants, wholesale, for resale to consumers, retail. Speaking through the voice of one Auctiva user, puppet-style, Alibaba opined: "I spend a lot of time online looking for products I can sell. I used to use liquidation sites, but AliExpress is much better, and more reliable."

If a line like that doesn't set the electronic-wholesalers at Overstock.com (Nasdaq: OSTK), Liquidity Services (Nasdaq: LQDT), and GSI Commerce quaking in their flip-flops, well … they must not be paying attention.

Who's it help?
Apparently, it helps the online merchants (or at least that one conveniently quotable merchant), who believe that by sourcing their merchandise from a single clearinghouse, they'll be able to lower their costs and increase their sales volume.

UPS (NYSE: UPS) could be another huge winner. As you probably recall, Alibaba began its big push into the international B2B sales game back in May, when its "AliExpress" subsidiary allied with UPS to establish a unified shipping and tracking system for Alibaba's Chinese supplier-customers. Having secured the logistics chain, Alibaba is now steadily securing the other links in its international supply chain. The longer that chain gets, the better for UPS -- and the more business FedEx (NYSE: FDX) can't transact.

The biggest winner of all
Where will Alibaba strike next? The company's promised to invest $100 million in expanding its B2B empire. While purchase prices for Vendio and Auctiva remain shrouded in mystery, CEO David Wei says he's still got "a lot of room" in his wallet before hitting that ceiling -- so your guess as to Alibaba's next bid is as good as mine.

Unfortunately for Alibaba, one prize still remains elusive. Since May, Alibaba's parent company has mused publicly about its desire to repurchase Yahoo!'s (Nasdaq: YHOO) 40% stake in the company. Unfortunately, the Alibaba.com subsidiary alone currently carries a market cap of nearly $9.7 billion, and while Yahoo! CEO Carol Bartz has promised to try and "monetize" that stake, I doubt she wants to do so at a discount.

Whatever Yahoo!'s asking price turns out to be, I'll guarantee you one thing: It'll take more than a piddling $100 million for Alibaba to consolidate its empire. When the price is finally named, Yahoo! will demand a king's ransom to free this Chinese prince.

Amazon.com, eBay, Liquidity Services, and FedEx are Motley Fool Stock Advisor picks, and the Fool owns shares of FedEx. United Parcel Service is a Motley Fool Income Investor selection. Motley Fool Options has recommended a bull call spread position on eBay.

Fool contributor Rich Smith does not own shares of any company named above. The Motley Fool has a disclosure policy.