At one time RealVideo was a de facto standard for anime fansubs, which have been used by anime fans to distribute movies and TV shows to areas where they aren't otherwise available. RealVideo became popular because of its (then) superior quality at exceedingly low bitrates. That has changed however with the introduction of MKV, and other MP4 containers.
Relevant Guides
How to play RMVB files- This guide will show you how to play RMVB files on your computer using several players not including Real Network's own RealPlayer.
