Absolutely not!!!!!!! Facebook will remain unbeaten as compare to twitter. Both sites are best but Facebook is on number one position all the time.
twitter is not too lively like facebook, people spent more time at facebook than at twitter. Facebook will always be the best .
i think twitter not take the place of Facebook. Now a days, facebook become a most popular social network for any Local business & information. Facebook implement graph search now which is like a google search engine when every one can find their friend post & information easily.