Facebook is vulnerable to hackers who can alter profile information without users' knowledge. Many pictures uploaded daily could contain viruses, though Facebook checks uploads it cannot catch all newly created viruses. Additionally, fake Facebook websites try to steal login credentials under false pretenses of viewing new photos. Heavy Facebook use can become addictive, wasting large amounts of time that could be spent on more important tasks. Prospective employers sometimes check applicants' social media profiles and unprofessional content could cost people jobs. Personal information shared on Facebook compromises users' privacy as everything is visible to all friends.