If I bought a Netflix subscription, I'd expect them to provide the Netflix service. If I bought a TV with a Netflix app on it, I wouldn't expect a partial refund from the people who sold me the TV. Do you honestly not see these two things are different?
One is "I paid for a service" and the other is "I paid for something to help me use a service".
Terrible analogy. If I buy a TV that has smart features or apps on it, I'm only marginally paying for the apps. It's even possible that Netflix is paying the TV manufacturer in order to be in the default install, so I'm not even paying for the apps; possibly I'm even paying slightly less for the TV than I otherwise would. (Even if that's not the case, that doesn't really change the calculus for me.)
So, no, if Netflix disappeared in this case, I would not ask for a partial refund. The TV still works as a TV, and that's what I really paid for in the first place. (If Netflix didn't disappear, but the TV app stopped working, I might be -- justifiably -- annoyed, though!)
This Twitterific thing is in no way comparable: the app only interacts with Twitter. That's its entire reason for being. If it can't do that, then it is worthless, and anyone who paid for it is perfectly in their rights to demand a refund. Hell, the Twitterific folks should be pro-actively refunding the unused portions of subscriptions; that's the only ethical thing to do here.
Did you ever own a dial-up modem? Was its only purpose for being that you logged into your ISP with it? Did you consider trying to get a refund when your ISP stopped providing dial-up service?
Yes, I did own a dial-up modem. In addition to connecting to my ISP, I spent many years connecting to various local BBSes. The ISP wasn't the only reason I had the modem.
And, regardless, if my ISP stopped providing dial-up service, and I really still wanted dial-up service, I would have simply found another ISP to connect to. (After expecting my previous ISP to issue me a pro-rated refund for whatever subscription I was paying them.)
Also regardless, your analogy is bad, as the modem was a one-time cost. The issue at hand is that of recurring subscription fees Twitterific charges. If we were just talking about a one-time cost to buy the Twitterific app, I wouldn't be suggesting the refund that cost (except to customers who just bought the app right before the shutdown, perhaps; seems shitty to keep customer money when the product irreparably breaks a few days after purchase).
Dial up was an on-demand pricing model, not a subscription. By your own rules that doesnt work.
Now, if you had dial up and paid a subscription for access to a free phone number and they cut you off before your subscription ended, then yes you absolutely would expect a refund.
You bought a display that exclusively integrates into Netflix, it can only display Netflix content, but you have to pay an annual fee to the display manufacturer for it to continue working.
It's January and you've just paid your annual subscription. But on the 15th of Jan Netflix decides to stop allowing your display manufacturer access, and your display becomes a useless brick.
Having only just paid for your annual subscription you'd want a refund - you're no longer getting access to the service you were paying for.
We can keep coming up with anologys but the fact remains that the app developer guaranteed access to a service which they can no longer provide. It doesn't matter if its an app, a display, or anything else. Your agreement is with the app developer, not Twitter. Your payments go to the app developer, not Twitter. If the app developers entire business is built around hoping Twitter never closes off their access then thats totally on them when things go south.
One is "I paid for a service" and the other is "I paid for something to help me use a service".