Though both are social networking websites, there exists a lot of differences on how they reach us, how they are utilized and how they work. Facebook launched officially in the year 2004 by Mark Zukerberg is originally a social networking site from its birth, but that is not the case with Twitter. Twitter is also a micro blogging site and Twitter project is an inspiration from Flickr.
Facebook is a place where you can post everything including your photos, video clips, status updates and can share them to your friends and they may in turn share or like your posts. But that is not the case with twitter, here you are allowed to post small messages like SMS and you can follow your friends to get tweets from them daily. You call posting in Facebook and Tweet in twitter. But both attracted millions of users within a short period of time. However they became business minded and they are in a position that they can even influence a nation's government or a stock index. You can get a better idea if you use both of them for a few weeks.