You know, if LinkedIn sent a percentage of that money on to the user, I'd be more likely to read the recruiting spam.
They guarantee that you will receive a response from an InMail within X days, or you get your InMail credit back.
I'm curious, how is this different from normal messages?
Edit: after thinking about it, I guess the fact you're paying to message someone would impress the recipient, thus enticing them to reply.
They call it 'InMail'. The difference is that the recipient has to make an action in the message, or your money returns. You have some InMails according to the plan you chose to pay.
By read, means somebody clicked on that page?
By read they say that somebody read and decided not to respond. After somedays, they will give you your credit back.