The output looks quite clean, I am not sure why it would be useful to have that option? Not at all! Why do we need something like this?? We are using html tidy as part of our development process (which includes unit testing) so having some way of validating my code before pushing changes out makes sense - although admittedly there's nothing wrong with manual validation if you're happy putting your hand through everything every time :) Definitely use when working collaboratively or where things get missed by other developers who may only look after their own area/files etc but don't validate themselves thoroughly enough.