By Kevin Kelleher, contributor

FORTUNE — Has any company in the technology sector seen higher highs and lower lows in the past decade than BlackBerry?

If you remember, BlackBerry (BBRY) — which earlier this year changed its name from the clunkier if more poetic name of Research-in-Motion — once ascended to great heights. Ten years ago, it traded at a modest $15 a share. Then its reputation for making top-of-the-line phones with secure, reliable messaging — along with an early lead in the budding smartphones — pushed its stock up, up, up.

So far up that, five years ago, the company’s shares were trading around $145 a share, a tenfold increase in only five years. Bullish investors were confident the Canadian company that had created the best mobile phone ever — well, at the time at least — was poised to conquer the world. (RIM was once named Fortune‘s fastest-growing company in the U.S.) Instead smartphones got, well, smarter.

In 2007, the iPhone came. Consumers saw. And Apple (AAPL) conquered. For all the addictive allure of the bubbly BlackBerry keypad under your thumbs, and no matter how much easier it was to type emails and messages on it, the iPhone’s intuitive touchscreen and the seductive apps that came with it (Google Maps! iPhoto! Pocket Guitar!) pointed to a decidedly post-BlackBerry world.

In that world, BlackBerry has struggled to find its role. And here is where the lows got pretty low. That stock price of $145 a share? It came one year after the iPhone appeared. Last year, it descended to $6 a share.

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BlackBerry promised a touchscreen phone that could rival the iPhone or the many the Android phones developed by Google (GOOG) that had appeared in its wake. Delivering a new mobile OS that had bugs would be product suicide, so Blackberry perfected its efforts, even though it meant delay after delay after delay. And by the time BB10 finally arrived in recent months, many had written the company off for good.

Here’s an illustration of how some investors had given up on the stock. Nine months ago, when BlackBerry’s stock was trading near its recent lows, bearish investors had sold 88 million shares short, or two days its average daily volume (termed “days to cover” in Wall Street parlance). At the end of May, short interest had mounted to 171 million shares, or nine days to cover.

In that time, BlackBerry’s stock has risen from $6 a share to $14 a share. Yes, that’s more than double its price last fall, but consider: It’s still a tenth of its price five years ago. When the first
Iron Man
 movie came out, you could have bought this company’s stock for $145 a share. And now that
Iron Man 3
is in theaters, you would have a dime for every dollar you invested.

Reading headlines about the Apple vs. Samsung battle, you might think it’s all over for BlackBerry. But not everyone thinks so. There remains a strong contingent of analysts and investors who think the worst days of this company are behind it. “We remain negative on BBRY and believe a turnaround to sustainable profitability based on BlackBerry 10 appears increasingly unlikely,” James Faucette said in a recent note for Pacific Crest.

Against this tide rides the return of the BlackBerry believer. Some people — maybe not-so-crazy people — think this company has a second act ahead. And they have some arguments they’d like you to hear.

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Take Andy Perkins, an analyst with Société Générale. Last week, he sent out a research not that sent BlackBerry’s stock rising 6%. He started off with an equivocating assertion that no one really knows how many BlackBerry phones are being bought, but his count suggested something encouraging: Four million this quarter, up from 1 million a quarter earlier. Based on early U.K. sales of the Q10 and Z10, “handset sales have been faster than we previously assumed,” he wrote.

Yes, that’s a fraction of the 30 million-plus units of iPhones and Galaxy phones expected to be sold this quarter, but it also shows that BlackBerry is still a horse in this cutthroat sweepstakes. No, no one expects it to lead right now. But hell, it’s doing a fine job just riding with the herd.

Although Perkins saw his metrics as uncertain by Wall Street terms, he took the bold step of upgrading BlackBerry’s stock to Buy from Sell and raising his price target to $17 a share from $13 a share.

A day later, Maynard Um of Wells Fargo weighed in, supporting Perkins. Um reiterated his Buy rating and said that sales of BlackBerry units were selling well enough to justify higher earnings than the Street was expecting. All that follows a bull-versus-bear debate on CNBC where the bulls made the company’s strongest case in quarters, as well as analysis among independent observers, who have been pounding the table for a BlackBerry comeback.

Of course, bears remain vocal too. (The stock is down 3% today on another downgrade, this time from Bernstein Research warning that expectations were getting too hopeful). But what’s significant about BlackBerry is that there is an argument going on about its future. Even that was hard to imagine a year ago. On the one hand, yes it’s hard to say this company will return to its former glory. On the other, it’s just these kinds of clashes of sentiment that can sometimes signal a turnaround in a stock.

BlackBerry has come back from its recent lows, but it has far to go to even begin to approach its highs. That itself wouldn’t be remarkable, except that the company’s believers have come back. Whatever you think about this company’s prospects, that development deserves some consideration.