WebMD ( WBMD) tumbled 10% after the healthcare information company warned of a third-quarter revenue shortfall.The New York company said it expects to make between $10.8 million and $11.7 million for the quarter ended Sept. 30, up from $500,000 a year ago and above its prior guidance of $8.2 million to $10.6 million. But WebMD said revenue will be $86 million to $87 million, below its previous target of $89 million to $94 million. "We continued to experience strong sales growth of advertising and sponsorship programs in the pharmaceutical, bio-tech and medical device markets this past quarter," said CEO Wayne Gattinella. "However, the timing of the launch of these programs is more weighted to 2008 than we had expected. Additionally, as we have previously discussed, we have been experiencing a lengthened sales and implementation cycle in our private portals business." Shares fell $5.99 to $52.