Google just don't stop, they've just announced that they're using their own data to detect viruses and will (as of today) be using Google Search results pages to warn users if their computers are infected with a specific form of malware. If a user has the virus, which is reportedly rerouting traffic to Google and other sites through a proxy will see the warning shown below.
A Google blog post titled "Using data to protect people from malware" says:
Recently, we found some unusual search traffic while performing routine maintenance on one of our data centers. After collaborating with security engineers at several companies that were sending this modified traffic, we determined that the computers exhibiting this behavior were infected with a particular strain of malicious software, or "malware." As a result of this discovery, today some people will see a prominent notification at the top of their Google web search results.
Google's Matt Cutts has shed light on the subject via his Twitter account saying that it only affects Windows-based systems and hijacks Google results. "That's how we learned about it," Cutts says about the "results hacking", without offering more detail on the subject. This is the first time a major search engine turns its results pages into a virtual malware alarm. This is a great step by Google as it causes headaches on their side if they just sit on their hands.
Instead, they've donned the tights, with a big "G" on the chest and have flown in to help users.