Job aggregators collect job postings from thousands of sites for you to search. They are the true "job search engines" of the Internet, and one of them is quite large -- the largest collections of job postings on the Internet.
As a result, on an aggregator site, you can search through jobs you would have never found on your own because you would have never found the source without spending quite a bit of time researching online and off.
Aggregators collect job postings from other sites and store them in one very large database to be searched by job seekers. Think of them as narrowly-focused search engines -- Google (or Bing) for jobs, only for jobs.
They show you jobs which were posted on employer websites, association websites, and newspaper classifieds. They also often include sites that may surprise you , from well-known job boards to many other job sites, large and small.
Postings from Craigslist have been excluded (Craigslist's choice), but many other sites are included -- many more than you could find and search on your own, even if you had the time to look for them.
[MORE: Using Craigslist to Find a Job.]
Because of their focus on jobs - only jobs - they have additional functionality that makes them much easier to use for a job search. Want search results sorted by employer? By posting date? By full-time vs. part-time vs. contract? Posted by employers or recruiters?
Because they have access to information, because they accept automated “feeds,” that may not ever be available on a search engine or may become available at some later point in time.
Because all they have is job postings, the good ones will only return search results that are jobs.
They also have the typical job site functions, like saving and e-mailing search results to the job seekers.
[MORE: Using Indeed to Find a Job.]
This may well be another "hidden job market," but this secret job market is full of job postings. Aggregators pull job postings from small job sites, like associations you would never know about (unless you used Job-Hunt's Association Directory).
And aggregators pull jobs directly FROM EMPLOYERS' websites - employers that may be unknown to you or that you would not have the time (or take the time) to track down and check out the website, if you did know about them.
Job aggregators provide a one-stop-shopping snapshot of the job market at any given point in time. When someone has a question about whether jobs in a particular field are available in a specific location, the first place I check is an aggregator site. The gross number of jobs listed is an indicator of the popularity and availability of that kind of job in that place.
Several types of aggregators are available now.
Indeed usually has the greatest number of results, and Indeed allows search results to be sorted by employer, job title, and location (left column of the search results). Indeed provides job aggregation in many countries, not just the USA.
Indeed also offers "Job Trends" which allows you to discover what employers are seeking by analyzing the millions of job postings Indeed has collected over the years. Read Choosing the Best Keywords for Your LinkedIn Profile to understand how to use Job Trends as well as their power.
Post your resume at Indeed Resume to be found by employers and recruiters, but protect your privacy (and your job if you have one). You can store a resume to use when for applying for jobs. That resume is also available to be searched by employers. And, of course, employers can post jobs directly on Indeed.
LinkUp is much smaller than Indeed, but it has specialized in one source of job postings. LinkUp aggregates only the jobs which are posted on employer websites.
Next: Tapping the Hidden Job Market - more ways to find jobs.
Online job search expert Susan P. Joyce has been observing the online job search world and teaching online job search skills since 1995. A veteran of the United States Marine Corps and a recent Visiting Scholar at the MIT Sloan School of Management, Susan is a two-time layoff “graduate” who has worked in human resources at Harvard University and in a compensation consulting firm. Since 1998, Susan has been editor and publisher of Job-Hunt.org. Follow Susan on Twitter at @jobhuntorg and on Facebook, LinkedIn, and Google+.