A common practice when creating sites in Drupal is to create different node types for different purposes. Sometimes these node types can be functionality based rather than content based and are used for creating a rotating banner or something similar. A side effect of this is that you will then see these nodes appearing in search results, which can cause some confusing results to be displayed.
So how do you remove these nodes? Well with quite a simple little module you can intercept the search query and stop certain node types being searched for. Adding a couple of extra functions means that we can add form controls to the advanced search form and the search admin area so that nodes can be selected to be excluded from the search results.