Monster is well-known for its hosting of users' resumes, both for comparison purposes, and so that potential employers can search through qualified candidates to find an ideal fit. Monster's database puts a worker's resume in the larger context of their skills, work history and general suitability.
Monster is an example of a certain kind of employment site that puts its members into a large pool and then subdivides them based on their particular skills and experiences. This makes that pool searchable by employers with very particular needs who may wish to process through the applications of only those who meet their exacting standards.
Websites like CareerBuilder also embrace this strategy and provide those seeking employment or new employment with a place to host their credentials. The appeal is that CareerBuilder and Monster are fishing grounds for powerful employers. They can provide paths to success and to new opportunities for those who host resumes on their sites.
Many online employment sites offer this particular feature. It has become a standard by which business is conducted, as employers would have a harder time accessing the talent they need if they were forced to wade through fields of applicants whose qualifications varied and whose experience was not immediately available to hand.