Some notes on indentation from an accessibilty's point of view:
The problem with indentation is, that indentation is only a visual concept. There must be a way for screenreader users to get informed about an indented text. Using lists (like Moin) or blockqoutes for indentation is a semantical misuse and I think not wanted by most accessibility experts. Using only css and divs (because indentation is only a visual concept) there is no way for screenreader users to get to know about an indentation of a text. There are ways to overcome this but as you can see, from a blind's view - I guess - indentation is a though topic.