By the end of 2009, recruiters following social recruiting where quite involved with LinkedIn and Twitter and Facebook. About 25% of UK companies where using social networks for recruiting.
Although LinkedIn was created for a more professional and business audience, it has evolved to be a great tool for sourcing talent and hiring candidates. LinkedIn accelerated that market by introducing more recruiter-friendly tools, like LinkedIn Recruiter and a host of other hiring tools.
Twitter 
Facebook
