Even sites that I know started as free but started taking money just to keep the site operating still provide LOTS (if not all) of their website for free.
Several online comic strip sites do this. UserFriendly, Joy of Tech, Goats are three I can think of off the top of my head.
I know that 'powers that be' have their own thoughts and ideas and possibly issues, but the point I'm trying to make (I think ) is that you can still provide content to an interactive audience (all 3 of the above have forums and a devoted following), and have advertising (as pixies has done) AND still accept donations from those willing to donate, and above all, keep operating - WITHOUT feeling like they've 'gone commercial' or 'sold out.'