I discovered the problem when my wife could no longer read my stories — not even the three free ones. Not a problem with her in particular (I pass her my iPad to read them) but it means I stopped posting links to my stories on FB.
I only recently joined the paid writers program, after starting to write on Medium in 2015, because it seemed like my readership had dropped off and I suspected my free stories were not being promoted. And yup, my reads have jumped since (enough to pay for my membership, not enough to pay for our next cruise). But I will still write for free if I have a story that I want the general public to read.