Facebook confirmed yesterday what some users have been noticing for the past few days: the social networking site is having problems.

The issues have included disappearing content, difficulties logging on, being unable to view profiles, and error messages when posting content.

"We are working to resolve these issues as soon as possible," Facebook said in a brief message at its Help Center.

The problems resulted from internal issues rather than a hacking incident like the one that affected Twitter, Facebook and some other sites early last month.

"We started experiencing issues this morning because of database and caching problems. We have a team of engineers working to restore the fast and reliable experience users have come to expect from Facebook," the company said.

Last week Facebook said its membership had passed 300 million, and that the company became cash-flow positive during the last quarter, something it hadn't expected to achieve until next year.

As its user base continues to grow, Facebook faces "fun and important challenges" like making its site perform faster and more efficiently, CEO Mark Zuckerberg said in a blog post.