Adobe Systems, known for its Photoshop editing program and Acrobat document software, announced overnight that it has agreed to buy web analytics firm Omniture for $1.8 billion (£1.09 billion).

The San Jose, California-based Adobe said it will make an offer to acquire all of the outstanding common stock of Omniture for $21.50 per share, a premium of 45 per cent over its average closing price for the last 30 trading days.

"Adobe customers are looking to us for solutions to deliver engaging experiences and more effectively monetise their content and applications online," Adobe president and chief executive Shantanu Narayen said.

"This is a game changer for both Adobe and our customers," he said in a statement. "We will enable advertisers, media companies and e-tailers to realize the full value of their digital assets."

Adobe, which also produces the Flash and Shockwave software used in many games and internet applications, said Omniture will become a new business unit within Adobe and Omniture's chief executive, Josh James, will join Adobe as the senior vice president of the new business unit.

It said the transaction, which is subject to regulatory approval, is expected to close in the fourth quarter of Adobe's 2009 fiscal year.

Adobe announced meanwhile its net profit fell to $136 million (£82 million) in the third quarter, which ended on August 28, from $191.6 million (£115 million) a year ago.

Revenue declined to $697.5 million (£422 million) from $887.3 million (£537 million) in the same quarter a year ago.

Adobe shares shed 4.18 per cent to $34.15 in after-hours electronic trading in New York.