According to News24, the campaign also seeks 'to help explain to consumers the risks of Google Shopping's newly announced 'pay-to-rank' practice,' a Microsoft statement said.
Microsoft created a Web page called 'Scroogled,' that says its rival has reversed course on its pledge at the time of the Google stock offering to avoid paid ad inclusion for search results.
"Google Shopping is nothing more than a list of targeted ads that unsuspecting customers assume are search results," the software giant claimed.
According to the report, Google maintains that merchants cannot improve their rank simply by paying more, and that sellers who have a financial stake in the results will keep their information up to date.
"Google Shopping makes it easier for shoppers to quickly find what they're looking for, compare different products and connect with merchants to make a purchase," a Google spokesperson said in an email.
Meanwhile, some analysts say both companies are less than transparent about how their shopping engines work, and that Microsoft is not without blame.