The discussions between Google and YouTube are still at a sensitive stage and could break off, says the person familiar with the matter. Other technology, media and entertainment companies have expressed interest in taking stakes in YouTube this year, according to people familiar with the matter. Google rival Yahoo Inc. earlier this week expressed interest in holding acquisition talks with the video start-up, these people say. YouTube also turned down a lower proposed value from Google earlier this week, before commencing discussions about the possible $1.6 billion deal.