Make it official: Google's not immune from the bad economy and plummeting ad market. We've been hearing for weeks that Google would have layoffs. Google is cutting 200 employees today, the company now confirms.

Google executive Omid Kordestani, the company's sales chief, wrote in the offiicial Google blog that cuts are concentrated in Google's sales and marketing operations, as tipsters told us earlier, and that the company had "overinvested" in areas where it had forecasted growth — growth which is not materializing. One source writes that the division that used to be DoubleClick before Google acquired the banner ad-sales network in 2007 was especially hard hit with more than 50 jobs eliminated in New York. Other sources say layoffs are spread throughout the Google empire; we've heard of at least one cut at YouTube.

A tipster writes:

A friend of mine in the San Francisco office's AdWords division (who wants to remain nameless) was laid off this morning. She also said there were 200 people total. They are still on payroll for two months and have the opportunity to apply for other jobs within the company. If they don't have another job at the end of the 60 days they get a severance package.

The 60-day payroll period sounds consistent with the advance warning an employer would be required to give employees affected by a mass layoff under state and federal laws known as WARN acts. If you know more, drop us a line.