OK, so everyone knows that LinkedIn is the place to go online to find work, but you might not know just how popular the networking site is among job seekers.

In the recently released 2012 Bullhorn Reach Rankings Report conducted by software-as-a-service recruitment firm Bullhorn, Inc., LinkedIn remained the most popular site for posting jobs. No surprise there. Overall, however, a remarkable 77 percent of openings were found to have been shared on LinkedIn, with Twitter and Facebook coming in at 54 percent and 25 percent, respectively.

Though LinkedIn leading the charge is hardly shocking news, some of the most interesting aspects of the survey can be found in the region-to-region analysis. The Northeast, for instance, was found to be most active in social recruiting, with a heavy emphasis on Twitter and Facebook. Meanwhile, the Midwest ranked least active in the social recruiting sphere and Facebook was most popular for recruiting purposes in the West, including Hawaii and Alaska.

"While LinkedIn continues to hold its position as the most widely used social network for recruiting, the fact that a majority of jobs are posted to at least two channels reinforces the notion that social networking should never be overlooked in any candidate's job search," Art Papas, president and CEO of Bullhorn, said in a release of the survey's results.

Staffing Agencies + LinkedIn = A Recipe for Success

The constantly rising popularity of LinkedIn as a recruiting resource for employers can be deceiving in some ways, however. Though an extremely beneficial tool, LinkedIn as a standalone service will not automatically lead to a sound recruiting process. In other words, you should lean on the site, but not too hard.

Specifically, the social media site can be effectively paired with a staffing agency. Staffing Talk compares the idea of LinkedIn replacing recruiting agencies to grocery chains serving coffee replacing local coffee houses. The publication cites one coffee house chain, Caribou, which responded to this business shift with the slogan "Sure you can get coffee for free at another store, but then you have to drink it." Completing the metaphor, if you want the best candidates, you need to dig deeper than LinkedIn profiles.

The relationship between companies and staffing agencies only improves with the growing popularity of sites like LinkedIn, as human resources professionals can do their own preparation and bounce ideas off the recruiting firms. On the other hand, the staffing service can help to identify passive candidates - those who may not be actively seeking a new position but would be a strong fit for an opening.