Compatibility
Countdown timers are basically an animated gif and offer a wide range of support in almost all email clients. The exception being outlook 2007+. Outlook, which will only display the first frame of the animation.
Usage
E-commerce sites can use countdown timers to highlight a limited time discount, or to countdown to the start time of a sale or event.
Educational and insurance industries can show a deadline or the end date to terms of service.
Retailers can pre-launch a promotion and highlight an opening or start day or time.
Banks and other agencies can emphasize a limited time opportunity available on a product or service.
