In the sentence “Facebook can be updated,” the word “can” expresses possibility rather than ability. It implies that updating Facebook is an option or something that can happen. “Can” is a modal verb that expresses: Ability – the capacity or skill to do something. She can swim fast. (She has the ability to swim fast. Possibility – something that is possible or allowed. This road can be dangerous at night. (It is possible that the road is dangerous.) Permission (informal) – being allowed to do something. You can go now. (You are allowed to go.) Request or Offer (informal) – asking or suggesting something politely. Can you help me? (Request for help.)