Copyright concerns

I figure if you have to plagiarise, then you're pathetic.  I can prove authorship of everything I've written, so I'm not too bothered, but I have put a lot of my own stuff out there uncredited anyway -- I've got lots of words to spare.  The internet is rife with people stealing other people's things and I think you'll go nuts if you worry about it too much.  If they're making money out of it and you find out, a quiet assassination is often best.