I ALSO buy the manga. (I like having a copy on my computer as well.) I have even gone so far as to BOTH buy RAW Light novels EVEN when RAW scan of said novels are available online for free and pay someone to translate them for me out of my own pocket when I could not find someone willing to translate them for free. And then provide said translations to everyone else for free online. (I run a VERY small group online called Fighting Dreamers Scanlations. Despite our name so far we have mostly done light novel translations so far. Mainly Slayers Special. I am currently Scanning the first chapter of the second book.) And I don't mind if other groups and or aggregators were to share them, because, call me crazy but I find it funny when my fellow thieves get self-righteous.
Speaking of which I'm pretty sure a site like that has bandwith costs. And unlike SOME sites I know they do NOT charge their users. (Narutoforums I belive, it has been a while since I have been in their download section