Google has announced it is to acquire communications security specialist Postini in a $625 million deal which the search giant says will boost the security and compliance capabilities of its Google Apps offerings to make them more attractive to enterprise customers.

Graham Titterington of analyst firm Ovum explained that it could prove to be one of Google's better recent acquisitions as the archiving, security and lifecycle management technology fits well with its own portfolio and could appeal to enterprises.

"Put all that with the connectivity and interface of a Gmail and you've got a pretty good managed service," he added. "But for a Postini customer the association with Google is probably not as positive."

Google will have to work hard on its Service Level Agreements (SLAs) in order to retain Postini customers who may be worried about recent privacy concerns raised by Gmail customers, he explained.

"This follows Microsoft’s purchase of FrontBridge two years ago, which provided similar email security to Hotmail," argued European managing director of messaging security specialist Tumbleweed. "Postini has approximately 10-11 million individual users but this move does not get them into the coveted enterprise space that Microsoft has infiltrated."

The deal is expected to close by the end of the third quarter 2007.