Yea, good question.
It depends on who you ask; what their experiences have been; and what generation you are talking about.
The channeling skill I learned and use is called conscious integrated channeling. With this skill, I am totally present to the experience while not interfering with your interaction with the being/entity I channel. Conscious integrated channeling is about allowing an entity with whom I have developed a relationship, to animate my voice to speak to you and animate my body to move around, while I am in the background, aware of what’s being seen and what’s being said.
The entity I am working with is not just any old entity who can jump into me whenever the “spirit” moves them. This channeling process occurs with an entity I have built a relationship with (really), and it interacts with me only when I request, not randomly of the entity’s own accord.
Trance channeling, which is an older form of channeling and which I have experienced as a customer, differs from conscious integrated channeling in that the channeler is in trance, meaning, they do not remember what the entity says, or what happens during the session. This is a much more common form of channeling. I understand that there are many channelers who still use this skill, such as JZ Knight, who channels Ramtha.
The term “medium” is more commonly used for people who can hear or see entities, and pass along messages from them to you. Usually, the entity working with a medium does not animate the voice or the body; the medium is more a spokesperson for the entity. This is what John Edward does, the medium who speaks to deceased people and has had several of his own tv programs.
I hope this helps. It’s my intention to continue answering the questions I receive from clients as I continue in my journey.