The top sources of quality hires have shifted in the past 4 years.

Four years ago, the top source for finding great people was referrals from your network. Today, it’s job boards and social professional networks – highly digital and targeted sources.
The growth of social professional networks as a source of quality hires mirrors the growth in membership of platforms like LinkedIn, which rose from 100 to over 300 million members over the last 4 years. The growth of job boards over the past year mimics the global uptick in the % of active candidates from 20% to 25% in the past year.
These changes signal the need for recruiting leaders to up-skill their teams on social professional network sourcing techniques and managing the process for active job seekers applying through niche and general job boards.

Companies aren’t capitalizing on the large passive talent pool.

Only 61% of global companies have a strategy for passive candidate recruiting. These are surprising stats, since the latest data on the passive/active candidate split shows that over 75% of professionals are passive — they would not proactively seek out and apply to jobs. That’s a huge talent pool to miss out on.
If you are yet to start developing a passive candidate recruiting strategy, these stats make a great case for why you should prioritize these efforts in 2015. Consider piloting a program with a recruiter (or a few) whose full-time job is to source and engage passive candidates. Then measure your results. For the same reason there are inbound and outbound salespeople and marketers, recruiters could also benefit tremendously from organizing themselves this way.
Global trends are here and it's time to rejuvenate the passion of hiring.

Resources & Insights - LinkedIn Talent Blog.