Git.io no longer accepts new URLs (github.blog)

Twitter doubled their character limits in a tweet while Twitter users adopted the concept of multiple tweets to form a thread. No other services (to my knowledge) impose character limits that would require url shortening.

More likely (though malware can contribute to this) they just can't justify the cost. There's always going to be a terse response that someone could build one in an afternoon and a $5 Digital Ocean VM, but bandwidth costs can be significant at scale.