Microsoft's "Scroogled" campaign gained plenty of attention last year when it called out the search giant's shopping tactics with regards to advertisements. Redmond is back on the offensive with yet another Scroogled campaign, this time taking aim at privacy concerns surrounding Gmail.

The latest national campaign is all part of a bigger plot to get users to switch from Gmail to by pointing out the fact that Google scans users' e-mails to find relevant advertisements to place alongside messages. The company cites a recent survey which found 70 percent of those polled were unaware of such activity. Unsurprisingly, almost 90 percent did not approve of the practice.

In a statement on the matter, senior director of Online Services at Microsoft Stefan Weitz said believes that privacy is not for sale. He noted that people should have choice and control over their messages regardless of the topic. Sensitive information like medical history or banking credentials should not be combed through by an e-mail provider.

For their part, Google has maintained that they aren't doing anything wrong by using automated technology to scan messages. The search giant said in a statement that advertising keeps Google and many websites and services they offer free. The company reiterates that no humans ever have access to e-mail messages or other account information with the intent of showing ads.

It's worth pointing out that also scans uses' e-mail messages but they only do so to search for spam and malware.