LinkedIn is a professional social networking site launched in 2003 that has grown to over 100 million members worldwide. It allows professionals to connect with colleagues and peers, find potential job opportunities, and build their professional brands. While LinkedIn provides valuable networking and career development benefits, users should be aware of potential privacy and security risks from oversharing personal information or connecting with untrusted contacts online. Managing privacy settings carefully and verifying connections can help maximize LinkedIn's value while mitigating risks.