I'm thinking about mashing up (old term I know) two services but I ran into a roadblock when I came across Yelp's ToS. The lawyers drew this thing up so tight I can't figure out any legitimate use of their API and have come across seemingly conflicting clauses. Take a look, its good for a laugh http://www.yelp.com/developers/getting_started/api_terms.
My question is, what have your experiences been with approaching companies about their API terms? Is there a good way to approach it? Obviously my biggest fear is spending the time to develop the service only to have them shut it done.