Aggregated Public Information Automated Email Site

I need a site created that will send automated emails to its members when specific data they seek is updated on public websites. The site will require a database, which can be updated by its users, that will list all of the data items of interest to them. The site will search public databases daily and any results that match the search criteria of a particular user will be emailed to that user automatically. The functionality of the site needs to be fully automated. Users need to be able to sign up on their own. They need to be able to update their profiles on their own, particularly their automated search criteria. The site needs to search the public websites on a daily basis, and then send out emails accordingly. I would prefer the site to incorporate a content mgmt system, though this is not absolutely necessary. I need someone honest, reliable, and competent. You will need to have positive feedback from other projects in order to qualify for this job. Thanks.