Now that gyms are functional again (and have spinnable Photo Discs) there’s a few things here that weren’t touched on during the update preview.
For starters “Super Effective” moves now dish out 140% damage while same-type-attack-boost moves (STAB for short) have been nerfed to 120%. It’s quite possible that Pokemon with double weaknesses might be in trouble when set to protect gyms.
Also, to earn coins now you need to defend a gym for at least an hour, where coins are awarded after your Pokemon has been defeated, and gym badges are awarded after spinning the Gym’s Photo Disc.
“Slashed” Pokemon won’t be able to damage those defending Gyms either so don’t be a cheater!
Last but not least, Gym defenders don’t start with full motivation but feeding berries to other Pokemon in the Gym will reward you with Stardust and Candies. Woo!
I’m not much of a Gym battler personally, but I’d like to go give it a go at least once. Go Team Instinct!