Apple's iPhone has had a remarkable run over the past year, shaking up the stodgy design of cell phones and securing Apple a lucrative slice of the wireless business.
To sustain that momentum and keep fickle consumers and Wall Street happy, the company needs a dramatic second act with the next generation of iPhones, which roll out today with faster Internet access and lower retail prices.
But even with Apple's untouchable image in the eyes of the Macintosh faithful, there are no guarantees for the company or its volatile stock.
After all, Apple has stumbled before in its foray into the cellular business, with a poorly executed price cut two months after the iPhone launch that left many early buyers fuming.
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And now that it's a significant part of the wireless market, Apple faces some of the same threats as more-established handset makers.
Among those pressures: intensifying competition and the uncertainty of a fractured market with many big players. There's also the risk that even with Apple's reputation, the iPhone might become so widely available that it loses some of the cachet that inspires buyers to wait in lines outside stores.
No one disputes that Apple and chief executive Steve Jobs have rattled the cell phone industry with the iPhone's design and features.
And Apple appears on track to meeting its sales targets for the iPhone – essential to appeasing investors.
However, unlike with the iPod, which became a blockbuster thanks partly to the device's tie-in with the iTunes music service, Apple faces a crowded field of entrenched competitors with the iPhone.
That means Apple must maintain the iPhone's cool factor as rival handset makers race to catch up. The landscape could look even tougher after new types of phones and applications emerge with Google's upcoming Android mobile operating system.
The iPhone is a small part of Apple's business – only 5 percent of its overall sales in the latest quarter. Macintosh computers and iPods typically generate 75 percent of revenue.
But iPhones are hugely profitable. By some estimates, Apple stands to make between $100 and $400 on each new iPhone sold, depending on the model and wireless carrier.
Investors have bet big on Apple's plans, pushing the company's shares up from $120 in March to around $180 today, mostly on anticipation that Apple will blow through its sales projections for the iPhone.
Put another way, though, anything short of a blowout could slam Apple's notoriously volatile stock. “To keep the stock price up, they'd have to do well, very well, amid high expectations – it's a very tough stock,” said Shaw Wu, an analyst with American Technology Research.
Apple has a target of selling 10 million iPhones by the end of this year. It's more than halfway there, having sold 6 million of the original iPhones before the supply ran dry in May.
But some investors question why Apple hasn't increased projections, even with two price cuts on the iPhone and the improvements in the new version – which is being launched in 22 countries, soon to expand to 70.