I just added a distant family member (wife of a first cousin, twice removed) named Mable Shaw. When I checked for duplicates, I also tried "Mabel" which I believe is the much more common spelling. There were three results for Mabel, none for Mable.
I kind of doubt anyone with a Mabel in their ancestry would think to try spelling it Mable and wondered if the good folks at WikiTree had considered adding a Soundex search.