IMDb and Rotten Tomatoes are both online databases that provide information and reviews about movies. IMDb was launched in 1990 and is owned by Amazon, while Rotten Tomatoes was launched in 1998 and is owned by Flixster. Both sites allow users to submit reviews, but Rotten Tomatoes reviews are primarily from professional critics, while IMDb reviews come from registered users. The document compares the two sites and includes reviews for the movie Saw 3D from each site.