A discount allows you to set up a date period where a discount will be applicable. For example, you can have a seasonal discount enabled in low season for weekly stays only. 

A special offer is a way of discounting a holiday stay. For example, if you have a holiday from 12th August > 16th August available you can choose to lower the price for this stay. A special offer can also be displayed as a stand alone page on your website using our integration links. It's a great way to display your offers in one place. You can obtain your special offer link via Admin > Website integration > Additional content. 

See below an example of a special offer page: