How much of a factor were the client limit and the API changes? I'd like to better understand if this is just you moving on or if twitter has made it impossible to continue your app.
Not impossible, but it's highly improbable to continue. The API changes aren't the biggest factor, but it requires some changes across the entire app, and I would like to take the chance to revamp a good part of it (It's major version 3, I've revamped it twice across the years already). Till now, they haven't answered me on how many user tokens I have used up, so it's a big risk for me to put in major effort, not knowing how much sales I can get in return. There's also some technical issue users are facing that they have been very slow to respond to (read: not yet), so frankly, I think I'm a low priority to them anyway.
I remember when I was on honeymoon and my web host fired me an email about blocking internet access because I was overloading their DNS server. I explained my situation (hey it's a production site and I'm away on vacation) and requested for them to keep me up for 4 more days when I'll be back home. They refused and I had to worked on it at the hotel, while my newly-wedded wife waited. I remember when I woke up in the night 2-5am, doing support, replying to users. I was fanatic about supporting users well.
I loved what I did. But that love has waned. Why stay when you aren't welcome?
Wow. I've never knew — but judging from a few emails I've got — I had some users of SimplyTweet from HN. It's sad, but it was fun while it lasted.