By default, when using ~share~ in a text, the system issues contacts a coupon the same way it does with ~redeem~. 

However, instead of the link opening on the main coupon page and description (when using ~redeem~), it opens on the coupon's share page (when using ~share~). 

The coupon share page functionality was developed in conjunction with "referral rewards" so that contacts could share coupons faster by opening directly on the share page instead of requiring them to click a share button on the coupon to access the share page.