Search king Google Inc. reported another billion-dollar quarterly profit yesterday.

Advertisers continued to flock to the leading search engine, boosting Google's first-quarter earnings by 69 percent to $1 billion — the second time it has hit the 10-figure mark.

The company blew past Wall Street's already enthusiastic expectations, defying analysts' predictions that slowing growth in the search advertising market would crimp Google's expansion. Its revenue jumped 63 percent, to $3.7 billion.

Rival Yahoo Inc. this week missed Wall Street's earnings expectations, but Google trounced them. Excluding stock-based compensation and other one-time items, Google earned $3.68 a share, compared with analysts' estimates of $3.30.

"True leadership and scale is translating into new opportunities," said Jordan Rohan, an analyst with RBC Capital Markets. "Web site owners need to respond to consumer demands. Consumers prefer Google. So, Google's the partner of choice."

Google shares fell $4.36 to $471.65 before the earnings report, then jumped 3 percent to $486.80 in after-hours trading.

Google is increasingly defining its core business as not just search advertising, but advertising of all types.

The Mountain View, Calif., company recently announced deals to broker radio ads for Clear Channel Radio and television ads for satellite TV operator EchoStar Communications Corp. "That's fundamentally our vision, that we can make advertising better for everyone," Google president Sergey Brin said.

But analysts say it's Google's focus on search-related advertising that continues to pay dividends.

Google spends about 70 percent of its resources improving the relevance of its search results and the user experience by adding handy features, such as maps next to a search for the local pizza joint. It's also made technical improvements that lead to more online sales by giving advertisers the tools to refine their online promotions.

"That's what really moves the needle," said Rob Sanderson, an analyst with American Technology Research.

This is precisely where Yahoo is still faltering. Its new and much ballyhooed search advertising system, known as Panama, has so far failed to boost the Sunnyvale, Calif., company's fortunes, as the company's first-quarter profit was off by 11 percent.