I don't know if it's open and shut either - but not because of the search analogy. That's covered in the CL ToS, sections 3 and 5. (http://www.craigslist.org/about/terms.of.use)
My problem is with section 3. CONTENT AND CONDUCT, part a, where they first state "CL does not control, is not responsible for and makes no representations or warranties with respect to any user content." Then it goes on to state that posters assign a bevy of licensing rights to CL for the use of the content.
How can they claim copyright to content and at the same time aver that they don't control it?
This is where the lawsuit gets _legally_ interesting. Craigslist can't really claim copyright over the listings themselves (see post above), but they can certainly restrict user rights through their terms of use (which is a contract). Generally, contracts can be used to reduce a set of rights a person has against another (e.g. waivers), but it cannot grant rights that they did not have in the first place.
So the first part of that statement is akin to waiver, so that someone can't sue CL for what the listings say. The second part is a claim on copyright and licensing, which they may or may not have.
My problem is with section 3. CONTENT AND CONDUCT, part a, where they first state "CL does not control, is not responsible for and makes no representations or warranties with respect to any user content." Then it goes on to state that posters assign a bevy of licensing rights to CL for the use of the content.
How can they claim copyright to content and at the same time aver that they don't control it?