IPTV over "Open Cable"?

Open Cable? describes the difference between what is called "internet TV" and what is known as "IPTV". This article references another in Xchange.

A snippet:

The announcement last week of Google Video, Yahoo Video and Media PCs from Microsoft, Intel (and likely) Apple have brought the issue of internet delivered television to the front burner.

But what is internet television? How does it differ from IPTV (or does it). Xchange Magazine explains it all.