Hi John, thanks for the question. We are currently running a small experiment in embedded Tweets to help us learn about how people interact with Tweets. This will inform future features.
The Tweet you’ve seen is one of a couple of compact variations enabled yesterday for a very small percentage of people. Please be assured, most of your users are seeing the regular version. It will return to normal when the test ends in about two weeks.
Small tests like this are run from time to time to inform our work, in addition to the feedback we get from speaking with developers and publishers. We’ll be in touch with the community whenever we decide to roll out features more broadly.