Listening to Google’s executives on their conference call with investors Thursday afternoon, you’d never know that the company’s second-quarter results fell short of expectations and its shares plummeted 10 percent in after-hours trading.

Since Google has chosen, as a matter of principle, not to offer any guidance in advance about what its sales and profits will be, it avoids any embarrassing questions if it misses its own marks. So Eric Schmidt, and other executives, blithely insisted that all was well.

Hal Varian, Google’s chief economist, said that while the company sees a bit of softness in ads for areas like auto lenders and real estate agents, other areas that might be economically sensitive are holding up, such as ads for home appliances. He suggested that Google is benefiting because shoppers look to the Internet for bargains.

“We have a little bit of the Wal-Mart effect going on,” he said. “As times get tough, people will watch their dollars, and in many cases, that means doing more shopping online.”

Some of the softness in Google’s advertising revenue, moreover, was self-inflicted. Jonathan Rosenberg, Google’s senior vice president for product management, said that Google had chosen to reduce its advertising coverage — the percentage of Web pages on which it displays advertising — to an all-time low.

That’s a puzzling decision on the surface. Virtually any other company facing slow economic times would be interested in increasing the places in which it could sell ads. It certainly wouldn’t take steps to reduce them.

But Mr. Rosenberg said that Google has no plans to increase its coverage because of its efforts to improve what it calls “ad quality” — the idea that Google should only show ads that users actually like. Mr. Rosenberg said that the company’s co-founder, Larry Page, would like to see even fewer ads.

“Larry often says we would be better off if we showed one ad — the perfect ad,” said Mr. Rosenberg. Mr. Page was not on the conference call to speak for himself.

But Sergey Brin, the company’s other co-founder, wondered aloud whether Google in fact had gone too far.

“There is some evidence we have been a little more aggressive in decreasing coverage than we should have been,” Mr. Brin said. He noted that Google developed technology that helped increase its revenue from advertising (largely by finding ads that are more interesting to users). Indeed, it had a rule of thumb that for every potential dollar the company could earn from an improvement in advertising revenue, it would reduce the number of pages showing ads so that Google would only earn 50 cents more in revenue.

“Clearly that is not the ideal strategy, because we don’t want to end up with no ads,” Mr. Brin said.

Investors, presumably, breathed a sigh of relief hearing that.