Twitter Buys Ad Security Company

Twitter has bought a small security company that specializes in protecting online ad networks against malicious ads embedded by cybercriminals. Financial terms were not disclosed.

The acquisition of Sunnyvale, Calif.-based Dasient is expected to help in securing advertising on Twitter, as the microblogging site builds out its revenue strategy. Dasient announced the purchase Monday through its blog.

Dasient was founded in 2008 by Neil Daswani, chief technology officer; Ameet Ranadive, vice president of products; and Shariq Rizvi, vice president of engineering, to focus on "solving Web-scale security problems involving malware and other types of online abuse," according to the company. A year later, Dasient started selling an anti-malware platform that scanned URLs and web sites for malicious content.

In 2010, Dasient launched an "anti-malvertising service" to protect ad networks and publishers against malicious advertising. Today, the company claims to protect some of the largest ad networks and web sites.

As a result of the acquisition, Dasient will wind down its business and will no longer accept new customers, the company said.

Dasient is the second security company purchased by Twitter in a couple of months. In November, the company bought San Francisco-based Whisper Systems, which provides security software for Android smartphones and tablets.

Twitter has been pursuing an ad-based revenue model since at least 2010, when it launched "promoted tweets" based on users' search terms. Late last year, the company launched a major redesign that introduced brand pages for advertisers.