Since RihannaVEVO is catching up to JustinBieberVEVO and is about to become the most viewed VEVO channel soon (unless Bieber releases more videos than Rihanna in the near future) I decided to make a thread where I will be daily updating the difference between these two channels.
Source:
http://socialblade.com/youtube; Youtube accounts of RihannaVEVO and JustinBieberVEVO
January 5, 2013 summary
JustinBieberVEVO: +3,488,837
RihannaVEVO: +5,400,700
Rihanna's gain: 1,911,863
View Goal: 3,500,000,000
JustinBieberVEVO: 63 days
RihannaVEVO: 61 days