These days, startups generally hit the headlines when they run out of cash and collapse.

But intriguing stories are also happening at "sounder" startups operating in areas previously considered promising, which raised massive sums of money over the last year.

A month ago the Israeli accounting firm Brightman-Almagor published its Fast 50 list, of the fifty startups that grew the fastest from 1999 to 2000. The criterion was the startups' valuation for the purposes of private placements.

The 50 startups named were ostensibly the soundest and most promising Israel could offer. They had grown the fastest, after all. But actually, the only reason some of them still look promising is that they are privately held.

If they were publicly traded, if they had to publish financial statements, if they were exposed to the cold gaze of investors and analysts - their fields would suddenly seem cooler, their business models less clear, their management problems more evident and their rapidly shifting focus would be glaring. Many still lack a clear direction or know if they will ever make a profit.

The most obvious example is

DealTime

, which provides price-comparison services for e-shoppers. DealTime made a high place on the Fast 50 list with a valuation of $400 million.

Not only is its $400 million valuation utterly detached from reality. The company's ability to sustain its operations, at least as an independent entity, is an open question. What helps DealTime maintain its reputation as a success is that it is a privately held company that managed to raise financing before the Wall Street crash.

Interesting times at Airslide

Then there's

Airslide Systems

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, which made second place in the Fast 50 list. Half a year ago Airslide raised an impressive $37 million at a company value of $180 million.

Airslide exemplifies another fascinating trend evident among startups in recent months: the secret executive shakeup.

You don't need insider information to see that times are interesting over at Airslide. All you have to do is visit its website.

The web-page showing the company's press releases of the last six months bears news of its position in the Fast 50 list, of its financing round, of a successful field trial, of the appointment of a new VP Strategic Planning, one Lenny Roth. Some of the press releases quote the company's CEO and founder Stephan Ouaknine. Others quote co-CEO and second founder, Oren Shmulevich.

But lo and behold, click on the "our team" page and you find that the CEO isn't Stephan Ouaknine or Oren Shmuelevich, it's Marc J. Zionts, who previously served as CEO of Westell Technologies.

Airslide does not mention when Mr Zionts was appointed. Unless you peruse old press releases, you might think he was the CEO all along.

"Psst. Who's that?" "The new CEO. Shhh!"

What's going on? Same thing that is happening at lots of startups these days. The board ousted the previous CEO, who was replaced with a professional manager. Ouaknine is now presented as the "vice chairman and founder".

Half a year ago the company trumpeted the appointment of a strategy veep. But it issued not a peep about what may prove to be one of the most important moves in its history.

Strange? Not really. Not a few Israeli startups have replaced their top executive in recent months. And they often do it hush-hush, in utter contrast to the crash of cymbals they generated for each little development or private placement in 2000.

The market has great respect for Airslide's technological team, and for entrepreneur Oren Shmuelevich. Also, as a privately-held company, Airslide is not obligated to report developments. And as a wireless-Internet company in general, for next-generation networks in particular, presumably the fervid enthusiasm inside the company and without has ebbed somewhat as the launch date for 3G networks disappears over the horizon.

Not only their CEOs have changed. For many of these startups, so have their business models and directions. They are also on a crash diet. And to top it all, now that venture capital funds understand that the chances of public offerings in the next few years are slim indeed the companies are forced to slash spending and find the path to profits, or to find a buyer.