Craigslist lawsuit against someone who made posting to Craigslist easier
IANAL but I've felt that craigslist's insistence on other sites from being able to use their data or submit data into their site constitutes a monopoly. At the very least they have been a bad stewart of a very useful and under-tooled set of important data.
Person's post in Reddit about this: http://www.reddit.com/r/IAmA/comments/ku5ss/i_was_sued_for_o...