Mounts increase your running speed, you cannot be dismounted when hit by enemies. To use your mount, first equip it and then press 'Z', to stop using your mount press it again.
Full list of mounts.
Giveaway Ends 4 days from now
Art Contest Ends 2 weeks from now
Event Ends 6 days from now
Seasons of Salt
Art Contest Starts 2 weeks from now