And Twitter has a lot of problems, chief among them that it is not a safe space! But maybe an unsafe space with lots of people is better than a space of indeterminate safety (I've been harassed on StatusNet) with relatively few people?
So, for twitter specifically, it isn't only about "stars" in that person's situation (probably), it could also be about following interesting orgs/etc (non-people).
And the "interesting orgs/etc" category won't come to the federated socweb until they have link click tracking tools that come preconfigured to support them (aka, never). See also: https://identi.ca/eff and https://identi.ca/creativecommons and <insert any other dead attempt at fed socweb from an org here>