I do believe that is exactly what search engines do. Are they breaking copyright?
This is not a simple question. Huge court cases have been fought over this. In general, things that get Google off the hook in these cases:
* Publishers have the ability to opt out of Google
* Where Google creates copies of information from other sites, those copies are provided to uses noncommercially (ie, they don't make more money when you use their cache).
* Google uses DMCA Safe Harbor to avoid liability, which again turns in part on Google honoring opt-out requests from publishers.
* Google's use of the data is transformative, an idea that in part turns on it not being a direct substitute for the original.
These are not generally arguments that bode well for PadMapper, which is effectively trying to compete with Craigslist using Craigslist data and a better interface. Publishers generally want Google to do things differently... but when push comes to shove, they also really want to be in Google's index. The same is not true for PadMapper.
Second, phone numbers are raw facts, but advertisements are not; every advertisement ever has been copyrighted, and a whole 11-figure industry depends on that.
