A marketing research firm is dimming its Internet advertising outlook for the next four years, the latest sign of the more austere times looming for the high-tech sector.

In revisions made Tuesday, eMarketer estimates U.S. advertisers will spend $25.7 billion on the Internet next year - about $2.7 billion, or 10 percent, less than a forecast from just three months ago.

The more sobering projections extend through 2012 when eMarketer envisions $37 billion being spent on U.S. online ads. That figure represents a drop of $13 billion, or 26 percent, from the 2012 estimates that eMarketer drew up in August.

Since then, the global economy has been rocked by the United States' worst financial crisis since the 1930s. The turmoil has included the collapse of big banks like Washington Mutual Inc. and Lehman Brothers, triggering a steep decline in the stock market despite huge U.S. government commitments aimed at restoring order.

The rescue plan hasn't been enough to prevent mass layoffs and home foreclosures either, pushing the U.S. economy toward its most severe recession in more than 25 years.

The pain increasingly has been hurting technology companies that had been viewed as safe haven until recently.

Both analysts and investors reasoned high tech would hold up better than most industries because corporate customers would still want to buy computers and software that helped automate their operations. Meanwhile, advertisers were supposed to be still spending money freely online in hopes of connecting with the Internet's expanding audience.

But those perceptions have shifted as more technology companies have acknowledged the tough times are crimping sales. The downturn has prompted already-weak companies like Sun Microsystems Inc. and Yahoo Inc. to resort to mass layoffs, but even stalwarts like Internet search leader Google Inc. are pinching pennies.

Investors already have been bailing out of technology stocks, including Google's, which has plunged 35 percent since mid-September.

Google's stock rebounded Tuesday on new research reports showing the company widened its already commanding lead in the lucrative Internet search market during October. The shares surged $24.61, or 9.6 percent, to finish Tuesday at $282.05.

EMarketer's new advertising estimates represent an even bigger comedown from another projection the firm made in March. Back then, eMarketer predicted Internet ad spending in the United States would hit $30 billion for the first time in 2009.

Although it's not as optimistic now, eMarketer still expects the Internet ad market to grow by 9 percent next year. That would represent a slowdown from an 11 percent increase projected by eMarketer for this year.

Google should remain the biggest beneficiary because its system for showing ads next to search results is expected to remain an effective marketing vehicle.

EMarketer predicts U.S. search ads will rake in $12.3 billion next year, up slightly from its August estimate of $11.9 billion.

Cisco Systems Inc. will close most of its U.S. and Canadian offices for 4 days over the holidays as part of a plan to cut $1 billion in costs in the current fiscal year, the company said Tuesday.

The shares fell 6 percent on fears that the move shows demand for Cisco's computer networking equipment remains sluggish, forcing the company's first mandatory shutdown in over a decade. The San Jose, Calif.-based company is forecasting that sales will fall 5 percent to 10 percent in the current quarter as the credit crisis strangles spending by corporations.

Cisco wouldn't say how many employees will be affected by the closure or how much money it will save because of the decision.

Many Silicon Valley companies have traditionally shut down over the holidays when business is slow and employees are on vacation. Some are now extending those closures, or revisiting a practice long since eliminated, in a bid to save money in a rocky economy.

Workers are usually either given paid days off or are asked to take unused vacation days.

Hewlett-Packard Co., for example, now plans to close its offices for two weeks instead of one. Apple Inc. and Adobe Systems Inc. are also asking employees to take time off.

Cisco's closure begins Dec. 29 and lasts through Jan. 2. The company describes it as a 4-day shutdown because it includes New Year's Day, a federal holiday when Cisco offices would be closed anyway.

Cisco said that "business-critical teams" including technical support and ordering services would stay open.