Salesforce.com ( CRM), one of the year's hottest IPOs, warned Wednesday that profit and revenue for the full year will be lower than expected, and the stock promptly plunged.

In a cruel twist, Salesforce.com shares tumbled $4.63, or 28.8%, to $11.43 Wednesday as chairman and CEO Marc Benioff rang the closing bell at the Big Board.

Salesforce Chief Financial Officer Steve Cakebread said at the company's first analysts' day that he expects fiscal 2005 net income of break-even to 3 cents a share and revenue of $160 million to $165 million, according to Reuters.

The three analysts who follow the company had expected a profit of 6 cents per share on revenue of $174.88 million, according to Thomson First Call.

When Salesforce.com went public in June, it closed its first day of trading at $17.20, a gain of $6.20, or 56.4%, the best first-day performance this year to date.