[skywhopper]

"I’ve built for hundreds of platforms and any changes to those platforms by default suck. At IFTTT, we've been on the receiving end of platform changes too many times to count."

Isn't that the entire premise of your service, providing this glue? Yeah, it's painful work. That's why people like your service! Sure, it would be great for you if the other services would do some of the work. But I'm guessing that you would not go along with Twitter requesting all intellectual property rights to your integration code for the right to use their API. Why would you request it of the services that integrate with you?

But the biggest problem here is that you changed the game. You created and maintained the Pinboard integration. You should own up to not wanting to maintain it. The message you sent to Pinboard users about your decision was... "misleading" is the nicest way to put it.