'Postpone' or 'postphone'?

Oh, please, that hurts. This is simply a case of the rise in a misspelling accompanying more people having access to publication, as you say.

"Postphone" is what happens after you drop your cellphone into the toilet, or if someone drives a car into the pole holding up your phone line. Or you run out of money and your carrier truns off your service.

Of course, "postphone" might be a telephone attached to a post. Hard to say for sure.

Except that whoever is spelling it "postphone" needs to be beaten with a wet noodle.

Horrifying.

The original word "postpone" hasn't changed either its pronunciation, spelling or meaning. The links that you have provided seem to have misspelled the word.

However, the correct meaning of "postphone" as per Urban Dictionary is as follows :

postphone

A verb meaning "to put off a phone call until a later time."

E.g. : I know you want to talk, but the plane's about to take off. We'll have to postphone.

You can view this link : http://www.urbandictionary.com/define.php?term=postphone