Several sources including News.com and the Yahoo Search Blog point out that HotJobs (a Yahoo company) is now using Yahoo's web crawler to enhance HotJobs own database with job listings posted on various sites and job boards across the internet. Yahoo calls the new feature its Job Engine.
This is similar to what Simply Hired and Indeed.com are already providing. In fact, both of these services include listings posted on HotJobs itself. Feedster also offers a jobs database that culls employment opportunities found in RSS feeds.
Note to Yahoo: It would be useful if you joined Simply Hired and Indeed.com in providing the underlying source site or database for each listing. This info can help a job seeker make sure their search is comprehensive but can alert them to resources they might not know about.
By the way, another way to access Indeed.com's database is via the "jobs" tab on Clusty. This way you can take advantage of Clusty's dynamic clustering to help spot potential job opportunities. Indeed.com and Clusty began their partnership in May.