(Reuters) --- Google Inc's YouTube said on Thursday the number of unique users visiting the video-sharing website every month has reached 1 billion, about six months after social media company Facebook Inc also said it had the same amount of users.

"Nearly one out of every two people on the Internet visits YouTube," the video website said in a blog post. (r.reuters.com/dev76t)

Facebook said it had passed the one billion user mark in September, a level of global penetration that has made its quest for sustained growth more challenging.