The differences between twitter and facebook are apparent.
Facebook: Facebook features include the, Friends, Fans, Wall, News Feed, Fan Pages, Groups, Apps, Live Chat, Likes, Photos, Videos, Text, Polls, Links, Status, Pokes, Gifts, Games, Messaging, Classified section, upload and download options and others
Twitter: Tweet, Retweet, Direct Messaging, Follow People & Trending Topics, Links, Photos, Videos
2. Instant messaging: Facebook supports but twitter doesn't
3. Number of users: Facebook: 1.15 billion+ Twitter: Over 500 million
4. Languages: Facebook: Available in 70 languages Twitter: Available in 29 languages
5. Follow trending topics: Facebook: No | Twitter: Yes
6. Post length: Facebook: Unlimited | Twitter: Limited
In all, they are all great tools to make friends and promote your business, hope my answer will be helpful!