Why I use a five star system...

So, it has baffled many a people (myself included) why many film critics use a 4-star rating system instead of a 5-star one.  Michael Medved, Roger Ebert, etc. all use quad-star system.  As it turns out, the precedent for using a non-4-star ratings was brought on by the advent of the internet.  Sites like IMDB and Rotten Tomatoes/Flixter have broken convention with their rating systems.  And I guess the reason that I use a 5-star system is because I rate every film I see on Rotten Tomatoes/Flixter, and that is the method they provide.  So, in case you were wondering, this is why I use the 5-star rating system.  Cheers.