I've seen people cross-post technical content on LI, but never use it as their main platform.
In any case, the best advice I got on LinkedIn was from a mentor helping me find my first SE job who told me: You don't have to like it, but you would be stupid not to use it.
In any case, the best advice I got on LinkedIn was from a mentor helping me find my first SE job who told me: You don't have to like it, but you would be stupid not to use it.