Adobe Systems and Omniture, Inc. announced the two companies have entered into a definitive agreement for Adobe to acquire Omniture in a transaction valued at approximately $1.8 billion on a fully diluted equity-value basis.

Under the terms of the agreement, Adobe will commence a tender offer to acquire all of the outstanding common stock of Omniture for $21.50 per share in cash.

"By combining Adobe?s content creation tools and ubiquitous clients with Omniture?s Web analytics, measurement and optimization technologies, Adobe will be well positioned to deliver solutions that can transform the future of engaging experiences and e-commerce across all digital content, platforms and devices," reads Adobe's press release.

Omniture charges customers fees based on monthly website traffic, so sales are less sensitive to economic swings than Adobe.

Advertising agencies and companies use Omniture's software to analyze how consumers use websites. It is the biggest provider of such services, competing with Google and other smaller players.