There's a couple sites specifically catering to the software dev for hire vertical, like Hired.

Though I think software devs have a unique view of Linkedin, in that we have many other avenues for professional networking AND we are heavily recruited at all levels of experience. When the only real way to network is via mutual acquaintances (as opposed to open source projects, chat rooms, etc.) and you aren't getting spammed with every "game changing startup" Linkedin can give you real value.