The majority of employers now allow applicants to complete formal job applications online.  We feel that including a written disclosure on their websites which state that the company conducts background checks would be ideal.  We always encourage our clients to post signage in their offices (preferably in areas where applicants complete their applications).  Not only does it deter job seekers who are trying to hide something in their background, it also shows your current workforce that you foster a safe workplace.  So if your company needs to hire individuals out of state, which necessitates that they complete an online application, placing a written disclosure on your website will serve the same purpose as if they were coming into your location.