Build online service like Google Alerts

I'm looking to build something like Google Alerts. I want to build a website hosted service that crawls websites/URLS on a realtime basis for certain specified 'keywords'. Once that keyword is found, I want an email to instantly notify me of the URL. Timing is key. For example: For the los angeles auto classifieds: [[login to view URL]][1] I want an email alert when a new ad for a "honda civic" is posted. The quicker the better. I also want room for expansion and scalability. Functionality wise it will only be used by me but eventually I want more users to use it. Just keep it in mind. Read description thoroughly and reply with your thoughts. Generic responses will be ignored. ## Deliverables ### Skills Required: [ruby-on-rails][2], [php][3], [mysql][4], [html][5], [javascript][6], [website-development][7]