When using the ContentSearch API what is the difference in using
Filter and can this have any influence on the results?
From the Sitecore documentation :
Filtering is similar to using Where to restrict the result list. When you use Filter, the scoring/ranking of the search hits is not influenced by the filters, and filters can be cached to optimize search performance.
To avoid influencing the ranking of the search results, use Filter when applying restrictions to search queries in the GetGlobalFilters pipeline.
From my understanding of these statements, I assume that a set of documents meeting the Filter criteria could be cached and from that document set different queries could then be run, which should be quicker than searching against the entire index. Is this all there is, or can Filter actually change the results that are shown?