Webmail accounts are often hit with less sophisticated, widespread attacks, too. Scammers like hacked e-mail accounts because they can use them to circumvent spam filters. Even users who do not handle sensitive information routinely find their Webmail accounts broken into and used to promote things such as illegal pharmaceutical websites.
Google has notified the victims of the attack and secured their accounts. The company has also "notified relevant government authorities," it said in its blog post.