Hi, I'm Prashant. I run Developer Relations at Twitter. I want to clarify a few things here.
In the past, Twitter had little formality associated with granting elevated access. It was very much, "Hey, I want to do this cool thing!" "Okay, sure, here you go." As Twitter's platform business has matured to include many businesses building billions of dollars worth of social media monitoring and other tools, we've formalized the process to becoming a Twitter Official Partner (partners.twitter.com). Over the last six months, we've started contacting all of those API key holders with elevated access and asked them to clarify what they're doing. In some cases, we know the business and business owner and reach out personally. In other cases, like this one, the business is listed in our systems as "N/A", so we send the template mail.
In the email, we encourage people who believe their app is within the bounds of acceptable use cases on Twitter to contact us directly, and provide a link to do so. The owner of this app elected to blog publicly about the situation before contacting us, which is unfortunate. We have contacted the owner of this app and hope to resolve this situation, as we do with hundreds of other developers on our platform. We do occasionally provide exceptions for apps that are non-commercial (not-for-profit, no ads, etc.)
Note also that in this instance, the notice is NOT about shutting down this app. It merely inquires about why the developer needs elevated access, something that is typically reserved for our business partners.
None of this is related to continuing to use the Twitter API or our commitment to enabling developers to build on our platform (Fabric, Gnip, our Ads platform, and the Twitter API).