Online tech media publisher TechTarget (NSDQ: TTGT) pre-announced its Q2 earnings, and lowered its forecast for Q3 on account of weakening macro environment. The formal earnings will be on Aug 13. The company expects Q208 revenue of $29.4 million, compared to consensus expectations of $31 million. Also, the company projects Q208 EBITDA of $7.5 million, compared to consensus estimates of $9 million. Total revenues are expected to increase to $29.4 million, compared to $24.6 million for Q207. According to CEO Greg Strakosch: “We believe that we are continuing to gain market share, however, due to the macroeconomic weakness in the U.S. and its impact on advertising spending, we believe it is prudent to reduce our guidance to reflect the current market conditions.” More details here.

Update: What makes the shortfall particularly interesting is that TechTarget’s ads are largely performance based, which Doug Anmuth points out in a note sent out this afternoon. Here you have all the big online publishers crowing about how they’ll weather the ad downturn, because they can shift to performance from brand based (see Yahoo’s conference call). TechTarget, you’d think, would have two layers of insulation from the economy: performance ads and a non-consumer, B2B focus. Anmuth still believes in a secular shift from brand ads to performance based, but it’s clear that the model is not a magic bullet.