Depends upon what you're hiring for. If you're hiring someone to find potential clients on LinkedIn and market/spam (read "do business development"), then some

Depends upon what you're hiring for. If you're hiring someone to find potential clients on LinkedIn and market/spam (read "do business development"), then someone already understanding the nuances of LinkedIn will help. For everything else, it doesn't give you any hints on how they'll do on the job. I know several talented developers who have not cared to create/build a LinkedIn profile. Focus on whether they have the skills to do the job and grow/learn fast.