The grandparent post was about FB and MySpace, not Twitter.

However, Twitter is a different beast. They got better over time because Twitter evolved from a friends network to kind of a interest-driven network. At the beginning people were following friends and then you had the same dissatisfying outcome like with FB (nobody wants to unfollow a crap-posting friend and muting wasn't available then). But nowadays you rather follow people on Twitter based on interest or because you share the same industry, etc.