From a reader:

I assume you already know this as the father of a young child, but everyone can see Snuffy now. Apparently, this has been the case for 25 years.

And from another reader:

Man, you’re dating yourself.
Sesame Street decided that having Snuffy invisible sent some kind of wierd message like grow ups won’t believe children … okay I’m lost already. Bottom line is the Snuffy is visible now.
Probably very few of your readers are under 5 years old and we all get the reference. Made me laugh.

This is not news to me.