Two trends have been very clear over the past year:
1) Facebook is becoming extremely popular on mobile, and
2) Facebook is focusing a lot of energy on building up their advertising capabilities and revenues.

So really it should come as no surprise that Facebook has recently acquired a mobile advertising company to help them advance both these efforts.

Rel8tion was founded about 9 months ago, and has operated in “stealth mode” ever since. As reported by All Things D, the Wall Street Journal company the broke the story, the Seattle based Rel8tion was working on hyperlocal advertising capabilities – namely the ability to link a person’s location and demographics to the most relevant advertising.

Clearly this sort of functionality would be very valuable to Facebook, who now has some 200 million mobile users. In fact, Facebook has consistently been one of the top mobile sites in all countries across Europe.

In addition, during the past year Facebook has shown its committment to mobile by launching several new mobile inititives such as the “check-in” service Places, and the mobile couponing service Deals.

For more on Place read Facebook Launches “Places”

For more on Deals, read Facebook Expands Mobile Marketing With New Mobile Voucher Service

In a public statement, Facebook confirmed the acquisition by saying, “We’re excited to confirm that we recently completed a talent acquisition of Rel8tion, a stealth-mode startup in Seattle. The engineering team will join our growing Seattle office, and we’re looking forward to having them on board.”

Last year Facebook acquired 8 companies, and there have been comments from the social network leader that this year they are planning that number to double. So I think we can expect to see more acquisitions of this sort – focused on monetization and focused on mobile – over the coming months.