Twit Cleaner, a popular web app used by hundreds of thousands to clear deadwood from their Twitter accounts, is the latest victim of Twitter's controversial API changes, as the site's sole proprietor, Si Dawson tells me: "It's simply technically impossible for me to continue."

By sheer coincidence, I had begun using Twit Cleaner just last week. It is gre ... make that, it was great. And it will be missed by users, some of whom Dawson describes as being "in grief" over its demise. He announced his decision on Sunday in a blog post that's striking both for the anguish it expresses and Dawson's magnanimity toward Twitter:

This week I worked 62 hours straight. Actually, that's a lie, I worked 65 hours straight, with 3 hours of naps. Twitter has stopped being fun. I started Twit Cleaner in 2009. Given that I haven't managed to develop a livable income out of it in that time (barring donations from you many wonderful, generous people), it's pretty obvious I'm not in it for the money. It's been my primary occupation over that time, and absorbed several thousand hours of coding, designing, building, testing and supporting it. Everything on Twit Cleaner (bar some low level server decisions), I've personally done. I wanted to make Twitter a better place for everyone. I love to code. I love helping people. That's it. Unfortunately, the new API is so crippling that Twit Cleaner is unable to continue.

The entire post is well worth reading. I also sent Dawson some questions via email.

Is there any chance you might reconsider? Have you received any offers of help or resources that might make that possible?

Unfortunately, it's largely out of my hands. It's simply technically impossible for me to continue, due to the radically tightened limits that Twitter introduced with v1.1. I do understand why they've done this - partly to get more fine-tuned control over usage, partly to smooth out demand peaks. If someone can make 20,000 calls in a minute, that's a gigantic drain on their servers. Multiply that by the 1 million apps they have, and that's a sys admin nightmare. The new model is much, much simpler to manage, from their perspective. Unfortunately, it limits developers to largely trivial applications (although I'm sure they'd disagree). Any of us who were doing more intense analysis are in some kind of pain. I have had many offers of help and resources. Unfortunately, they've all been on my side (where the problem largely isn't), and not so much from Twitter's side (where the problem largely is). I have talked to a bunch of people at Twitter, and they've been variously enthusiastic ("We don't want you to stop developing Twit Cleaner"), consolatory ("It's sad to hear this news"), and almost helpful ("You're using the API wrong, here's how..."). Unfortunately, none of this really addresses the core issue. I've had almost universally positive interactions with Twitter, so I don't want to bag on them. They're good guys, doing the best they can in a technically and financially challenging environment - 200 million users, and investors demanding a solid return.

What's been the reaction from your users? And your reaction to that?

There has been a massive outpouring of grief by the community, witness the comments (on Sunday's blog post and on Twitter.) Mostly the responses have been a variation on "Thank you for everything," "This is the best app ever," "We're sad to see you go, but understand," "Best luck for the future," "Twitter should hire you" and very commonly "I don't know how I'm going to live without you." It's been incredibly humbling. I really do have the most amazing group of users ever.

You don't seem angry toward Twitter. Are you really that good of a sport? Or do you believe there are things Twitter might have done or might do in the future to prevent situations such as yours.

The people I've interacted with at Twitter have always been patient, helpful and kind. Now true, I haven't been dealing with the guys at the top calling the shots - so I can't speak to their motivations. Obviously there's large pressure there to turn Twitter into a profitable business, but the guys I've dealt with who are actually getting the work done? I have huge respect for them. The more you sit down and think about what actually happens, on a technical basis, when someone like Ashton Kutcher tweets, and 14 million people instantaneously hear about it? It's a technical marvel. I'd never begrudge them doing what they can to keep that stable for all of us. It's definitely rough as the sands shift beneath your feet, but that really gets back to my primary lesson: Being a share-cropper (building something on someone else's platform) is a fool's paradise. Fun while it lasts, but ultimately doomed.

What's the plan for winding down the site?

People are welcome to keep unfollowing as much as they like (up to 500/day) on any existing (Twit Cleaner) reports they have, it's just no new reports will be generated. But at the end of March all the functionality will go away.

Dawson tweeted one more effect that he will feel personally.

At least he hasn't lost his sense of humor.