On Friday, @Road (NASDAQ:ARDI) was about half the company it was the day before. On the news of its earnings release, the stock plunged nearly 50%. Yes, it had a stock split the hard way.

The company is in a hot market: mobile resource management. That is, it provides services and solutions for wireless, such as integration, transaction processing, and location detection. The focus is primarily on field workers, who need access to customer relationship management data, inventory, and scheduling.

The business model is also popular: hosted applications, which are how leading companies such as Salesforce.com (NYSE:CRM) provide their own technologies to customers. @Road has also been wise in leveraging the marketing and infrastructure of key partners, such as Nextel (NASDAQ:NXTL), Verizon (NYSE:VZ), and Sprint (NYSE:FON).

But this is irrelevant for Wall Street; rather, these fickle portfolio managers want a company to hit its numbers. Well, no doubt, @Road veered off a cliff, although, on the face of it, @Road's numbers were strong.

The firm posted a profit of $3.1 million for the second quarter, which was up from a $227,000 loss a year ago. The earnings missed Wall Street by a mere penny. Revenue was also up 16% to $18.3 million and missed estimates by only $600,000.

So, what was the problem? As is often the case, the real news came in the conference call. Basically, @Road did not provide its net subscriber growth number for the quarter. In other words, there is probably weakness in subscriber growth -- if there is any.

Wall Street is always a demanding crowd. But in the current environment, investors seem to be ultrasensitive to bad news. And, for the most part, investors are willing to believe the worst.

In fact, there is another consequence to @Road's poor performance: The stock price meltdown imperils the company's plans to acquire Mobile Data Solutions (NASDAQ:MDSI). In other words, the firm will probably need to re-up on the price.

Fool contributor Tom Taulli is the author of The EDGAR Online Guide to Decoding Financial Statements . He does not own shares in any of the stocks mentioned.