The online recruitment agency would have an interface via which job seekers can upload their CV. This is stored in our database,  and is made available to potential employers / recruiters.
Employers would log on to this application and provide a detailed description of the job vacancy that exists in their organization. The web application would extract the relevant keywords from the job description. regular expressions would be used to match these keywords found in the job description. The percentage match of every CV stored in the database is used to assign ranking positions. In the end, the highest ranking CV - that which has the highest percentage of matching keywords -  is served first on the list.