On a work item, there is a handy button that will 'find potential duplicates' for me. I was wondering if anyone could give me a little bit of detail on what this is actually doing...

Does it just search the summary for similar words or does it also use text from the description and maybe even the comments?

If I search for duplicates and it doesn't find one that I know is a duplicate, is there any way I can teach the search for the future?