Having a central repository of resumes and how those people are connected is valuable. Seeing that I know someone who knows someone else is useful when applying for a job or reaching out as a salesperson. Even just knowing that a position with x title exists at y company is useful when searching for jobs or clients.
I’m on bluesky. It got most of the twitter people I followed for humor. The protocol supposedly allows (will allow?) other servers, but for now I think it’s mostly the one. I prefer mastodon governance/structure, but bluesky has a bunch of people I want to read.