Where do you think most job seekers begin their search for a new job? Most recruiters will tell you that candidates start by searching on the big job boards like Monster, Dice and CareerBuilder.

And those recruiters will be wrong.

Ten times more job seekers start their job search on Google than anywhere else.  (Update: I have not been able to verify this statistic elsewhere, and it clearly uses global information, not just the United States.)

Where do small employers post their jobs? When I ask HR managers where they post their open jobs, they usually rattle off a list of job boards. But they almost never mention Indeed. Yet three recent studies found Indeed to be the number one external source of hire for employers in the US.  (Not coincidentally, all three surveys were from companies that provide Applicant Tracking Systems that integrate seamlessly with Indeed: iCims, SilkRoad and Newton Software.)

How did that happen?

It’s simple, comScore research shows that two out of three searches of any kind originate on Google. And Google job searches often lead job seekers to Indeed. See for yourself. Type your own title and location into the Google search bar and see what comes up. The first few jobs you will see are probably posted on Indeed. Consequently, Indeed has three times more unique visitors per month than CareerBuilder (80 million vs 24 million). (UPDATE: In January Indeed had 100 million visitors)

But the bigger threat to small employers long term is not Google upending the job boards, it’s mobile and social.

According to comScore, more than one out of every three minutes spent online is now spent “beyond the PC” on smart phones and tablets. Already 30% of Indeed’s total candidate visits are mobile. They encourage it. Both Indeed and CareerBuilder have mobile apps that let candidates apply to jobs from their phones with minimal effort … as long as the employer enabled the mobile-apply functionality. But very few small employers make their job ads and career sites mobile friendly … because many small employers don’t have a career site.

In a 2012 study by Potentialpark, 77% of recent college grads expect to see a company career site and 94% go on to say that in addition to the career site, employers should present themselves on at least one social or professional platform. 61% expect employers to have a Facebook career page, and more than half expect a company page on LinkedIn. And if you disappoint them, they will be vocal about their job search experiences. 92 percent say they discuss their job search experience with others, both in-person and through social media.

So let’s sum this up. Only 4% of job seekers start their job search with a specific company in mind. So if your ads are not in the right place to be seen, you won’t be considered. And if somehow candidates do see your ad, many will not apply if your application process is too much of a hassle. And if they do apply, and don’t enjoy the experience, they just might leave a bad review about your company on Glassdoor or Indeed, scaring off everyone else who might consider working for you. (I called this trend, “The Amazonification of Recruiting” in a post on The HR Examiner.)

Employers, this is your wake up call. In the past 3 years, almost everything you took for granted about job advertising has changed.

DISCLOSURE: This is not an endorsement of any vendor. I am not paid by anyone mentioned in this post. I am however, a client of Careerbuilder, iCims and Indeed.