FORTUNE — In the United States, “Alibaba” doesn’t have the same ring as “Amazon,” “eBay,” or “Facebook.” Not yet, anyway.

But as soon as today, the largest e-commerce website in China — and, according to some estimates, the world — could file for an initial public offering in the United States. It could be quite possibly one of the largest public offerings in history. (Or at least since Facebook’s (FB) blockbuster IPO in 2012.)

An IPO does not a household name make, but Alibaba’s offering is poised to be too big to ignore. The company is often described as a mix of Amazon (AMZN), eBay (EBAY), and PayPal (PYPL) — all successful U.S. technology companies for very different reasons. Alibaba’s top properties, the consumer-to-consumer online shopping portal Taobao and the business-to-consumer sister site Tmall, together attract more than 100 million unique visitors each day and are among China’s most visited websites.

MORE: Memo to tech startups: If you want money, raise it now

Which means that if you’re shopping online in China, it’s highly likely that some of your money ends up in Alibaba’s coffers. Four out of every five dollars spent online in China goes to an Alibaba marketplace. Last year, during Single’s Day — China’s version of Cyber Monday in the U.S. — Alibaba’s top two marketplaces brought in $5.75 billion in 24 hours. That’s double what all U.S. online retailers are estimated to have made during last year’s Cyber Monday.

“Alibaba is huge,” said Yan Zhang, a professor of strategic management at Rice University and an expert on Chinese businesses. “It’s one of the best-known names in China.”

Most investors know Alibaba because of Yahoo’s (YHOO) sizable stake in the company, which dates to a 2005 deal negotiated by Yahoo co-founder Jerry Yang and Alibaba CEO Jack Ma at a time when it was popular for U.S. technology companies to invest in promising Chinese Internet businesses.

Today, Yahoo owns 24% of Alibaba and must sell two-fifths of its stake when the company makes its expected offering. The Sunnyvale, Calif.-based company stands to benefit as Alibaba’s revenue growth picks up steam ahead of the anticipated offering.

MORE: Weibo Chairman on IPO: ‘We’re here for the long term’

“Holy Alibaba,” Bernstein Research analyst Carlos Kirjner wrote in a research note earlier this month after Yahoo reported its quarterly earnings. “Alibaba crushed expectations posting year-over-year revenue growth of 66% and massive margin expansion.”

Analysts generally expect Alibaba to raise at least $15 billion in its offering. (To compare, Facebook raised $16 billion in its 2012 IPO.) Kirjner estimates the possible valuation of Alibaba to be as high as $245 billion, which would make it the ninth-largest U.S.-listed company on the S&P 500, just behind Wal-Mart (WMT). (Alibaba did not respond to a Fortune inquiry regarding the company’s IPO.)

What is less clear is how Yahoo fares in the wake of the offering. Investor outlook has been mixed for the company: Some see it turning around under chief executive Marissa Mayer; others see its Alibaba investment as a crutch the company will be without once it goes public, potentially dissuading some Yahoo investors from sticking with the (lower-growth) company.

“If you wanted to own Alibaba you invested in Yahoo. Now you can own Alibaba directly,” B. Riley analyst Sameet Sinha told Fortune.

MORE: Weibo’s IPO: Rough sailing ahead?

Sinha added that he doesn’t anticipate big winners and losers in the wake of Alibaba’s IPO. The offering will merely allow Alibaba to raise a lot more capital and become more transparent.

“Beyond that,” he said, “I don’t think it’s going to have much of an impact from a business standpoint because a lot of the U.S. companies don’t have the same geographic footprint [as Alibaba].”

That may soon change. Alibaba is reportedly looking to bring its e-commerce business to the U.S. and is ramping up its investments in U.S.-based companies. (Ahead of its IPO, Alibaba participated in a $250 million funding round for ride-sharing app Lyft, as well as invested about $200 million in the U.S. retail site ShopRunner and $215 million in the mobile messaging app Tango.) The company is expected to launch an e-commerce site, 11 Main, “where hand-picked shop owners connect with customers in a stylish and professionally merchandised marketplace.”

MORE: Is time running out for Marissa Mayer?

It’s far from certain that Alibaba will succeed in these endeavors. Chinese companies have faced significant challenges in the U.S. market; for example Weibo, China’s answer to Twitter, raised less money than it expected in its U.S. IPO. Other Chinese tech companies have delisted from the New York Stock Exchange because of lower-than-expected valuations.

One of the largest challenges for any Chinese business seeking to go public in the U.S. is managing concerns about transparency, said Rice University’s Yan. How Alibaba manages those concerns and how other investors respond to the IPO could have a major impact on Chinese businesses in the U.S.

“It will be very important for other Chinese companies who are also considering U.S. IPOs,” Yan said. “If Alibaba’s IPO does well, it will encourage other Chinese companies, especially technology companies, to consider IPOs in the U.S. market.”

FROM THE FORTUNE ARCHIVE: An upstart takes on mighty eBay (2004)

And it could have a big impact on the broader IPO market, which appears to be slowing down.

“The IPO market hasn’t been the best market recently,” Sinha said. “The market has been volatile. Maybe the Alibaba IPO, priced correctly, paves the way for other companies to go public as well.”

Whatever happens, Alibaba will leave a lasting impact on the market, Sinha said. “This is one of the most highly anticipated IPOs in a long time.”