A lot of sites I build (with IDX Broker) just have a few different types of search forms that allow a search of all MLS listings. Then's there's some slideshows/showcases that feature the Realtors own listings more prominently.

What more do I really need that a custom IDX provides? Like what fancy functionality do you guys use with your custom IDXs that would generate more profit? I hear a lot about more "functionality/flexibility" but I don't really know what that specifically translates to on the website.