LinkedIn initially rejected two bug reports from me. The first was fixed. For the second one they just deleted a post I couldn't access when logged in. Now I want to build an alternative. Every account can have a resume, post jobs, share stuff with mentions and private messages.
I've always hated Linkedin. It feels bloated and spammy. Angellist and StackOverflow have been much more convenient to find companies that are a good fit for me and vice versa. Looking forward to see what you come up with. Good luck!