SALT LAKE CITY -- Top of Utah residents are invited to participate in RootsTech, the largest paid family history conference in the United States, coming March 21-23 to the Salt Palace Convention Center."We are fortunate to have such a world-class conference right here in our backyard," said Paul Nauta, spokesman for the event. "We have over 250 classes and speakers. It's getting bigger and bigger."Now in its third year, RootsTech 2013 is evidence of the increase of family history interest and technology, said Nauta."There has just been an explosion in the last few years for social value with Pinterest and Facebook," Nauta said. "The core of all these emergings is the need for people to connect."