This Postini acquisition, more than any other previous development or acquisition, marks Google's entry into Web Office for enterprises (of course we already knew they were competing with Microsoft in office software, but now there's no denying it). As Rajen Sheth, Product Manager, Google Apps, noted on the Official Google Enterprise Blog, "larger organizations are frequently forced to choose between taking advantage of the latest innovations that will make employees more productive and ensuring security and corporate compliance." The implication being that enterprises have thus far been reluctant to use Google Apps due to security and compliance reasons - preferring the more robust, desktop-based solutions offered by the likes of Microsoft and IBM. Sheth also mentioned Google's recent release of email migration tools, which "have already been used to migrate millions of email messages from legacy systems over to Google Apps." See also the blog post of Dave Girouard, Vice President & General Manager, Google Enterprise; who extends the theme of servicing enterprises.

Finally, I thought the NY Times had a good take on this - summarizing how Google's Web Office is evolving. Concluded Saul Hansell:

"...if Google does succeed in convincing companies to accept advertising on their internal systems, it may become the replacement for trade journalism. Instead of advertising your widget maker in Widgets Today, you could simply buy an ad on Google that will appear every time someone reads an e-mail or writes a presentation about making widgets.

That’s several steps down the road, of course, but Google is playing this game for the long term."

Google is of course already experimenting with this, as there are ads in Gmail now. But I agree with Hansell, Google is in this Web Office game for the long haul - and right now they are buying all the right companies and slowly piecing the jigsaw together. I think we'll look back on the Postini acquisition as the day when Google officially jumped into the Web Office for Enterprise space, even though they'd been building up to it for some time.