Google acquired email security vendor Postini in 2007 in hope to strengthen its online services. It took less than seven months for the giant to integrate Postini's line-up in its own portfolio.  Today Google announced the availability of its new enterprise filtering offering.

Google Apps already offered several commercial services distributed online (the infamous Software as a Service model). Until now they were quite focused on productivity softwares like email, instant messaging, word processor or spreadsheet. They now are complemented by three optional security services, Google Message Filtering, Google Message Security and Google Message Discovery. The first service filters spam and malware out of email messages for $3 per user and per year. Message Security deals with viruses and offers outgoing filtering rules, all for $12 per user and per year. Finally, Google Message Discovery adds message archiving and searching to the previous services, for $25. It's to be noted that Google seems to have forgotten about encryption and TLS routing rules Postini originally brought to the table with the acquisition.

Customers do not have to use Google's existing email services to benefit from the new security services. They are compatible with enterprise class messaging solutions as Lotus Notes, Microsoft Exchange and Novell GroupWise.

About 500,000 companies already use the Google Apps and they are, of course, prime targets for Google. Most of them are SMBs and should not be put off by Postini's simple web administration. About 35,000 companies, totalizing 10 million users already use those security solutions.

Well entrenched within SMBs, Google now needs to seduce larger corporations, usually quite timid when it comes to the Software as a Service model. And Google does not have yet much to offer to larger companies outside of SaaS.