Q: Is it okay to send LinkedIn invitations to people you don’t know but want to network with in a job search?
A: I applaud you for “networking from your chair.” Yet, it’s less likely that cold LinkedIn requests will get good responses. Instead, I suggest you reach out to people you want to network with (through your own or the vicarious good will of others) by email, and afterward send them an invitation to link.
LinkedIn has useful information on which of your contacts is a contact of or could introduce you to another person. Use that aspect of the site well; it is one of its best features.