The group Minnesotans for Marriage is upset about a Facebook campaign launched by opponents of the Constitutional amendment that would define marriage as an opposite sex union. The tool being distributed by amendment opponents allows Facebook users to identify and contact friends who might support the measure.
To Minnesotans for Marriage, the tool amounts to stalking and harassment. Minnesotans United for All Families sees it as a modern version of the phone banks that campaigns have used for decades.
It's called the 'kNow tool" and if you have a Facebook account you can see it for yourself here.