This morning I noticed a question on the Welcome mat and I  also received  this question . . .
What does ''SHOW BINDING'' mean as a finish for a hooked mat?
I think the reply is anyones guess!

You could  cover the edge with wool fabric  like we hooked the rug with . . .cut on the straight of grain or the Bias (-click for how to . . .)
. . .but I myself usually hook rugs for the floor . . .so I would not use wool fabric . .not strong enough.

I have recently finished a repair  EDGE of an antique rug that was  bound with fabric that over the years just disintegrated . . .. 

I found that BLACK cotton CARPET  BINDING TAPE worked well and hid all the backing and hopefully will last a long time!
Notice all the  beautiful blacks the fabrics  faded into over years of use!I have re-hooked a few spots . ..they look ok to me!

MORE TIPS on BINDING A RUG with CARPET  TAPE underneath the rug click HERE