Shares of SodaStream (NASDAQ:SODA) popped more than 13% during intraday trading Tuesday after the company's investor day spurred upgrades from a number of analysts.

All told, the stock is currently up a whopping 20% over the past five trading days since the Israel-based company posted stronger-than-expected results. But why, exactly, is everybody so excited today?

The $1 billion question
To be sure, I was impressed just a few days ago when the folks at SodaStream raised full-year guidance, telling investors they now expect 2013 revenue to grow around 27% to just over $554 million. Meanwhile, 2013 net income should also increase by around 20% to $52.7 million.

Yesterday, however, SodaStream management went even further, telling investors they hope to generate annual sales of at least $1 billion by 2016 -- for those of you keeping track, that would represent a more than 80% increase in sales on top of the company's already-impressive numbers. As a result, analysts at Oppenheimer raised their price target for SodaStream to $68 from $60, and the folks at Citigroup raised their price target on the stock to $66 from $60.

What about now?
As it stands, shares of SodaStream are currently trading around $65 per share and 29.5 times trailing earnings, so I can't help but wonder whether the stock is finally beginning to look a little too rich to buy. 

Of course, I thought the same thing about Lumber Liquidators back in February after its epic 200% run over the previous year, but the flooring specialist proceeded to rally another 44% to remind me why it's dangerous to doubt the potential for stocks of admittedly great businesses.

After all, as I noted last week, there are currently more than 130 million households in the United States, of which SodaStream has penetrated less than 1%. Contrast that to SodaStream's more established markets like Sweden, where a full 25% of all households use its products, and its potential becomes that much more enticing.

That's not to say maintaining the growth will be a walk in the park, especially considering beverage behemoths like Coca-Cola (NYSE:KO) and PepsiCo (NASDAQ:PEP) will certainly be loath to release their iron grips on the largest soda market in the world. Heck, even Warren Buffett once stated, "If you gave me $100 billion and said, 'Take away the soft-drink leadership of Coca-Cola in the world,' I'd give it back to you and say it can't be done." It should come as no surprise, then, that Buffett owned 400 million shares of Coca-Cola through Berkshire Hathaway at the end of 2012 -- good for an 8.9% stake currently in the company worth almost $17 billion as of this writing.

However, this also serves to highlight one of the biggest reasons SodaStream should be able to continue growing quickly; even after the recent rally, SodaStream's total market capitalization sits at only $1.35 billion, or more than 140 times smaller than Coca-Cola's and 95 times smaller than PepsiCo's.

Foolish final thoughts
While investors shouldn't expect Coke or Pepsi to fall from grace anytime soon, remember that it'll take much less to move SodaStream's revenue and earnings needles.

In the end, I'm convinced SodaStream represents another one of those truly great businesses, and I wholeheartedly agree with the analysts who say this small company is only just getting started.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.