Microsoft are buying companies again. This time it's e-mail security provider Frontbridge Technologies Inc.
FrontBridge provides an outsourcing service that allows companies to have their e-mail and instant messaging scanned before it reaches internal corporate networks. FrontBridge's subscription service also allows companies to back up their messages and comply with regulations.

In February, Microsoft said it would acquire Sybari Software Inc., which develops software that protects e-mail systems from worms and viruses, as well as spam, or unsolicited e-mail.

Microsoft, which has had a major push over the last three years to improve the reliability and security of its software, said it expected to close the FrontBridge acquisition by the end of September. Terms of the deal were not disclosed.