Rumors - some now confirmed - have been flying about the possible sale of two hot internet properties, Facebook and YouTube.

Social-networking site Facebook, which has been expanding beyond its core audience of college students, is apparently in negotiations with Yahoo to be acquired for possibly up to $1 billion, according to the NY Times Dealbook blog, which cites a Wall Street Journal article. Facebook has apparently also held separate discussions with Microsoft.

A Times article on Friday confirms that Yahoo has offered about $900 million for Facebook and says it would grant some autonomy to the company, with founder Mark Zuckerberg remaining in charge. The model is similar to that of other Yahoo acquisitions, such as photo-sharing site Flickr and social-bookmarking service Del.icio.us.

Meanwhile, online video site YouTube is apparently holding out for $1.5 billion in a potential sale - a "magic number" that, according to the New York Post, is far above what media executives are willing to pay for it.

Earlier this year, Facebook's founders said they sought $2 billion in a sale, with Viacom said to have offered $750 million.