Frankly I find the "Relevance" sorting idiotic and useless. There seems to be no rhyme or reason to how it finds the most relevant content when I'm trying to search for a layer, map, or app on ArcGIS Online. It's not in any sort of order, and deprecated items still find themselves higher up in the list than authoritative items. I can't find any technical specification on how this "Relevance" sorting is supposed to work either.
I always end up going to the "sort by" button and changing that to "Date modified" to find the most recent thing I worked on.