Even a billion dollar company can make a big mistake. Seems as though Google emailed people a virus. According to a message posted to Google Video blog:

On Tuesday evening, three posts were made to the Google Video Blog-group that should not have been posted. This has now been addressed and fixed. Still, some of these posts may have contained a virus called W32/Kapser.A@mm -- a mass mailing worm. If you think you have downloaded this virus from the group or an email message, we recommend you run your antivirus program to remove it. If you do not have an antivirus program, you can download Norton AntiVirus software for free from the Google pack, http://pack.google.com/intl/en/pack_installer.html?nopers We're sorry for any inconvenience, and we're taking steps to ensure that this doesn't happen again. The Google Video Team
Oopsie! Maybe Google should install anti-virus in their messaging systems as a fail-safe mechanism. Doing that is much less painful than experiencing the embarassment of mailing people malware