Google posted strong quarterly revenues and earnings this afternoon, beating Wall Street estimates on both counts. But also notable was the number that the company reported for its overall employment: 20,621 permanent workers, an increase of nearly 4 percent over the fourth quarter of last year.

Looking back at the numbers, that's the biggest sequential increase in jobs at the Internet search giant in two years. Google executives said previously that they would begin hiring again, and the new numbers show that they're solidly back in that mode.

No, it's not a return to the double-digit growth that the company was experiencing prior to the recession, but it's a particularly notable trend given that Google was particularly early among technology companies in slowing its hiring when it noticed the economy turning down. The trend underscores the company's optimism about its prospects for growth in the coming years.

The quarterly increase translated into a net gain of about 800 employees for the company worldwide. On a conference call with Wall Street analysts, company officials said they expect to continue hiring "aggressively" this year, focusing in particular on engineering and sales positions.

That promises to have an impact on Microsoft and other tech giants that compete with Google for top talent, including engineers coming out of computer science programs. The search company has large offices locally in Kirkland and in Seattle's Fremont neighborhood.

Update, 2:26 p.m.: Asked about the hiring trends on the conference call, Google chief financial officer Patrick Pichette said the company is seeking to maintain its high standards even as it boosts hiring.

"We have talked about, ever since last summer, that we are trying to ramp up our machine to hire back, specifically in engineering, specifically in the support of sales, where we see great opportunities. It takes a couple of quarters to ramp up the machine so that we get levels that we want. We're very pleased with the hiring that we've done," Pichette said. "The bar at Google -- let me reemphasize that -- has not changed. It is incredibly high. But we're very pleased with the onboarding that we've seen this quarter. Now that this infrastructure is in place, you can expect to see us continue to invest heavily in this form. We have so many projects that we would love to have more engineers right now, that we would like to fuel our growth. It is really paramount to continue to focus on that."

Pichette later cited Google Chrome as an example of the projects where the company is hiring, without saying whether he was referring specifically to the Chrome browser or to the upcoming Chrome PC operating system, or both, given the crossover between those two.