I just wrote a crawler for a client who needs to check vendor licenses (plumber, electrician, etc). Given a license number, state, and trade, it looks up the appropriate licensing agency in that state and pulls the license info (issue/expiration dates, biographical information, infractions, etc). Luckily most of these are old school sites so they're easy to crawl, but a few have captcha (easily solved with OCR) or are single page apps.