Google has spent an enormous amount of cash in developing and acquiring entertainment and information services, whether it be their search engine that started it all, their desktop utilities, YouTube or many others. Could they now be making some headroom into the PC security market? Without much fanfare, Google has acquired GreenBorder Technologies, which is a company that sells anti-malware software. The basic idea behind GreenBorder's software is that it isolates software, particularly browsers, from the rest of the system as well as other programs. This approach is seen in other ways, to limited degrees, with virtual machines, sandboxing and other features that you can find in modern OS's.

Google has their sights set on other areas of the PC security market as well, such as anti-virus. Their motives aren't clear, but their actions are:

It's clear that Google is pushing aggressively into the anti-malware market to clean up its own search results and provide protection to end users and this deal signals the company's intent to use the browser as the entry point to get on desktops.
This is probably a good thing. The anti-virus market is dominated primarily by Symantec and McAfee, with other players like TrendMicro filling niche needs, and the anti-malware market is composed primarily of freelance work. A company like Google might be able to offer something a cut above what we currently have. Considering the rapidly increasing threats that rogue sites bring, more powerful anti-malware software may be in order.