Five Things You Are Doing Wrong When Approaching Candidates on LinkedIn

Candidates are not going to waste time speaking to you unless they can see real opportunity for themselves. If you don’t have a specific vacancy at that time, explain to them why they should engage with you – let them know you have some fantastic connections in their industry.
http://www.social-hire.com/social-recruiting-advice/4407/five-things-you-are-doing-wrong-when-approaching-candidates-on-linkedin