What does PHP do for a website?

Also Cron Jobs which can implement tasks from one minute, hourly, daily, weekly, monthly or once every year.

I use daily to download a XML spreadsheet, convert it to a CSV file then update a database of books. Over 22,000 books takes about half a minute to update.

IOT (Internet of Things) can be interfaced to hardware monitoring devices for irrigation crop control, temperature and humidity, car parking availability, etc