Vertical job search engines have hit the job board world like a tornado - there has been heated discussion about the future of job search engines (also known variously as job aggregators and job metasearch sites) but this is the only list that I am aware of.
First, the top 10 (North American) and traffic graphs from compete.com for the top five 
bottom five and for comparison's sake a Google trends graph for the top five:
updated 3-27-10
- indeed.com
- simplyhired.com
- topusajobs.com
- juju.com (job-search-engine.com)
- careerjet.com
- linkup.com
- jobalot.com
- justjobs.com
- gojobs.com
- getthejob.com
And here is the comprehensive list. These are arranged by the location of the company because so many of the search engines operate worldwide:
Americas
- CareerCast.com (Adicio)
- DiversityJobs.com (LatPro.com)
- Eluta.ca (MediaCorp.ca)
- GetTheJob.com (EmployOn.com)
- GoJobs.com (Jon Duarte)
- GoogleBase.com (all classifieds)
- HudsonValleyJobs.com (LatPro.com)
- Indeed.com (VC backed, JobsInTheMoney.com founders)
- InSourced.com
- JobAlot.com (EmploymentGuide.com)
- JobGeni.com
- JobSearchAll.com
- Job-Search-Engine.com (Juju, Inc.)
- JustJobs.com (LatPro.com)
- Oodle.com (all classifieds)
- QAJobs.com (LatPro.com)
- SearchJobs.com (Net-Temps.com)
- SimplyHired.com (VC backed)
- TopUSAJobs.com (Don Firth)
- WowJobs.ca
Asia
- CareerJet.hk
- Faayda.com (India)
- JobBind.com (100+ countries, based in Amman Jordan)
- Recruit.net (covers Asian countries)
- TopCompanyJobs.com
Europe & Middle East
- CareerJet.com (French company)
- ICJobs.de
- Indeed.com (VC backed, JobsInTheMoney.com founders)
- JobBind.com (100+ countries, based in Amman Jordan)
- JobDaddy.co.uk
- JobsinHubs.com
- Joboter.de
- JobRapido.com
- JobSucher.ch
- JobWindow.com
- OpcionEmpleo.com
- WorkHound.co.uk
- WorkCircle.com
- Zamzim.com (for USA but owned by WorkCircle.com)
Now, more of these sites are surely on the way. So, we're moving closer and closer to a situation in which the same jobs are available on every job board. Who wins in that case -- the team with the best interface and results? The team with the best marketing? Will one company dominate in both areas? Who do you think it will be?
Or maybe when the venture capital money is gone, the largest sites will fold and the leanest of the bootstrappers will carry the torch. There's an interesting discussion about the viability of vertical search at Talentism.
My own belief? You can count on more than one long-run winner from this bunch - perhaps one or two of the generalist boards and a number of niche verticals similar to DiversityJobs.com. Who's your money on?
