In what could be the region’s biggest-ever day for tech deals, Westlake Village-based Conversant said it will be sold to Dallas-based Alliance Data Systems in a deal valued at $2.3 billion, and Santa Barbara-based Eucalyptus Systems said it will be bought by HP.

Both deals were announced after markets closed Sept. 11. Conversant, a digital marketing firm, is being purchased for cash and stock at $35 a share, a 34 percent premium over its recent price. Eucalyptus, a UC Santa Barbara spinout focused on cloud computing, will become a key part of HP’s cloud strategy, with Eucalyptus CEO Marten Mickos overseeing the company’s cloud group and reporting directly to HP CEO Meg Whitman.

Here is a closer look at each deal.

Conversant

Conversant was known as ValueClick until it rebranded earlier this year. In addition to its Westlake Village headquarters, the company also maintains a presence in Santa Barbara, where its affiliate marketing group formerly known as Commission Junction is based.

The company got its start with Internet display ads in the late 1990s. Over the decades, it acquired various units in emerging digital technologies, from affiliate marketing to more recent acquisitions in video. It operated like a conglomerate, largely letting businesses units run autonomously so long as they were profitable. But revenues took a hit in recent years as customers demanded a more unified online buying experience for their digital ad dollars. CEO John Giuliani undertook a major effort to harmonize the various units.

“The cornerstone of our vision is that we believe personalization is the future of marketing,” Giuliani said on a conference call with investors earlier this year. “We fully intend to be known as the personalization company.”

Alliance is has strengths in traditional direct mail marketing and email marketing. Under the deal, Conversant is valued at $35 a share and will be paid out with a mix of 52 percent Alliance stock and 48 percent cash.

Eucalyptus

Founded by UCSB computer science professor Rich Wolski, Eucalyptus focuses on open-source cloud operating systems that can interact seamlessly with commercial systems from Amazon and others. It’s useful when a company needs to have one part of its cloud infrastructure under its direct control but still wants to leverage publicly available services. The firm raised $56 million from investors such as Institutional Venture Partners, Benchmark Capital, BV Capital and New Enterprise Associates. It has 75 employees. About a third are based in Santa Barbara.

The acquisition price wasn’t reported, and it could very well be below the regulatory disclosure for HP, which had more than $100 billion in revenue last year. In a press release, HP said that Eucalyptus will be a key part of its cloud strategy. Mickos will become senior vice president and general manager of the firm’s cloud business, building out its HP Helion portfolio.

Eucalyptus was an early mover in the open-source hybrid cloud space. Though it had ups and downs as the ecosystem emerged, it did sign large customers such as NASA, the U.S. Food and Drug Adminstration and NetApp.

“Hybrid clouds are the vision of the future,” Mickos told the Business Times when the company raised $20 million in 2010. “In terms of the product, we are the pioneer in the field, and nobody has a product that is as mature as ours. That gives us a great lead in the market.”