I personally thought the big Twitter drama of the week was going to be the company’s move to replace its long-delayed free API tier with a “paid basic tier” – but then, Twitter decided to pick a major fight with Substack. Well, maybe Substack technically started it. The company announced a new Twitter-like Notes feature on April 5th. But a day after, Twitter started taking steps against Substack, first by blocking Twitter embeds in Substack stories. Then, it severely limited how you could engage with many Substack URLs on Twitter and then limited how you could engage with Substack’s actual Twitter account. It’s all a big mess, and it’s somewhat burying what could be very real impacts on the Twitter ecosystem as a result of the API changes. Popular Twitter bots like the Thread Reader App have relied on that free tier, for example, but they may now be forced to pay potentially exorbitant prices or cease operations entirely. The fabric of Twitter already changed dramatically after the company banned third-party clients in January.