Oracle (ORCL 0.73%) has made another in a string of acquisitions of digital marketing companies. The software giant announced it has reached agreement to buy privately held BlueKai, a firm that helps marketers track the web surfing habits of users in order to optimize ad targeting. The price was not disclosed, although an article in The Wall Street Journal said that "people familiar with the matter" put the cost at less than $450 million.

The deal is the latest buy in the digital marketing sphere for Oracle. Last year, it struck a roughly $1.5 billion deal to acquire email marketing specialist Responsys, and purchased marketing solutions provider Eloqua for approximately $935 million.

In the press release announcing the BlueKai deal, Oracle said the company's offerings would be integrated with Responsys for business-to-consumer marketing automation, and Eloqua for business-to-business marketing automation. These integrations are being effected "in order to deliver orchestrated and personalized customer interactions across all marketing activities and channels," said the firm.