The program is still in the experimental stage and will last fot three months . That may be the reason there is no official announcement yet. In addition to this program, there will be other programs too. For example, Medium will curate specific Lists of articles created for particular topics in the future. So, readers can find almost all the things related to a particular topic in one place. Medium will become the next "Wikipedia" on the internet. That's why "Evergreen" content (content that has long-term value to the readers) should be boosted rather than "News Type" and "Meta Medium" articles.