Just days after Google completed the rollout of its interest-based advertising service, WPP is jumping on the targeted-ad bandwagon with its own company that will link ad-buying technology with a massive database of consumer profiles, reports The Wall Street Journal.

WPP is set to announce the creation of Xaxis, a unit that will manage the "world’s largest" database of individuals’ profiles—including demographic, financial, purchase, geographic, and other information that’s been collected from peoples’ Web activities and physical transactions. This information will be used to create personalized ads for the Internet, mobile, and, eventually, TV.

According to WPP executives, Xaxis will have access to over 500 million profiles, reaching nearly 100 percent of the population in markets where it operates. Xaxis will build up this database by tracking consumers via ads and marketers' websites, as well as by tapping existing customer databases and buying information from outside firms.

Lawmakers and other groups have voiced concern about the practice of collecting, buying, and selling consumer data for use in such databases. But WPP says that all of the information it collects is anonymous, plus any ads using the data will include a special privacy icon that tells consumers that they are being targeted and allows them to opt out.

Xaxis, which reportedly is rolling out in 11 countries, will be used across WPP agencies and by clients belonging to Group M, WPP’s ad-buying unit. According to The Wall Street Journal, the companies that make up Xaxis managed about $200 million in digital-media spending last year, and that number is expected to grow rapidly in the upcoming year.