Shares of Infospace ( INSP) were savaged after the bell Tuesday as the search stalwart's second-half guidance was shockingly bad. The company, which reported solid upside in its June quarter on a 53% revenue gain, said third-quarter earnings would be less than half of what Wall Street wanted. The stock tanked $12.27, or 35%, to $22.52 in after-hours Instinet trading. For investors, Tuesday evening's episode flashes back to April, when the shares shed about 20% on a near-identical serving of decent earnings and downside guidance. The stock has now lost half its value this year. In the second quarter ended June 30, Infospace said, earnings rose 21% to $16.3 million, or 44 cents a share, on revenue of $83.2 million. Analysts surveyed by Thomson First Call had been forecasting earnings of 38 cents a share on sales of $85.4 million. For the third quarter, however, the company sees earnings of 15 cents to 20 cents a share, compared with estimates of 45 cents a share. It pegged sales at $75 million to $80 million, compared with estimates of $94 million. For the year, the company sees earnings of $1.15 to $1.25 a share on sales of $330 million to $340 million. Analysts had been forecasting earnings of $1.85 a share on sales of $376.8 million. In the second quarter, Infospace saw revenue in its search and directory segment rise 34% from a year ago to $46.1 million, while revenue in its mobile segment rose 85% to $37.1 million.