2016-06-08 : Activated abilities contain a colon. They're generally written “[Cost]: [Effect].” Some keywords are activated abilities and will have colons in their reminder text.

2021-06-18 : Activated abilities of noncreature permanents that would make them become creatures (such as a Vehicle's crew ability) can still be activated. Once they become creatures, any abilities they have cannot be activated.

2021-06-18 : Cursed Totem doesn't stop players from activating abilities of creature cards that aren't on the battlefield, such as cycling or unearth.

2021-06-18 : Cursed Totem stops players from activating mana abilities of creatures.

2021-06-18 : Other abilities of creatures, including static abilities and triggered abilities, are unaffected.