Knowing whether registered sex offenders live nearby is important to many people, and a free online and mobile service is a handy tool for keeping tabs on sex offenders in the area. The Bulloch County Sheriff’s Office website, bullochsheriff.com, has a link to a listing of local sex offenders, but the AlertID Inc., online and mobile service, including a smartphone application, provides alerts from state sex offender databases to 166 million people, or more than half (53 percent) of the US population. “I think this is a pretty good thing,” said Bulloch County Sheriff’s Capt. Todd Hutchens, the chief investigator for the department and who handles the county’s sex offender registry.