Hi Nat,
I wasn't comprehensive in the blog, so leaving out "replies" wasn't intentional.
"Replies" and TV certainly have a fit. Viewers "reply" to questions on TV all the time - they phone/text in, someone replies, they may have a chance to say more...another caller phones/texts in... etc.
I also didn't bring up the idea of "TV show" in the metaphor -- I think it would take a bit more thinking to decide where the concept of "show" fits in. Is a "show" some topic that you like to discuss? Certainly "shows" in TV land usually have designated times when they air, yet with DVRs/VCRs, people these days watch them whenever they want, fast forward through commercials, etc. I wonder if the concept of "shows" would be useful to us in Twitter?
All of my real-world experience with product metaphors has been "redesigning" to the metaphor, not really spontaneously thinking of it before a product exists.
Something like Flipboard (
http://www.flipboard.com/) feels like it couldn't exist without Facebook/Twitter/etc. existing first and folks wanting a better experience from those products/services.
best
jk