I was recently running through Caledon Forest, where I had 100% completion, when I had a message "[some area name] discovered" pop up. This also revealed the area on my map. It wasn't a point of interest, just a part of the map. Since I already had 100% for the zone, how am I meant to know if I've found all these areas? Do they count towards overall completion, or do they not count for anything?
What factors contribute to world completion?