the explosion of threads is because of twitter's algo...

to view a thread, you have to interact with a tweet. this interaction drives metrics that results in the tweet showing up more frequently in the algo-feed. the multi-post nature of a thread means there are more opportunities to "like/retweet" - which also drive the algo-feed.

all this increases follower count... and an audience (that's soon to be easily monetisable on twitter) is far more valuable than a blog... unfortunately