Originally Posted by PowerCum

Because if you convert it properly you can gain quality and still have relatively low bitrate. Most people wouldn't bother with that, but we do.
Having a HUGE library of scenes licensed from 1998 to now has left us with lots of formats bitrates and funky crap around. We are just reencoding and normalizing everything in our content library at the moment.
Lots of amateur made content using the first digital cameras or still old Hi-8 and VHS cameras requires some extra resampling if you want to put it on a production site nowadays... even if it's a free tube with full scenes like in our case