What is an ident/sting?

"A sting or ident generally comprises of a short animated video sequence that forms either a company logo, graphic or image. The length of a sting varies but typically lasts around 5 – 20 seconds. A sting’s purpose is to reflect the ideas/products/mentality of a company."

I think as idents are supposed to be short, I will not overload it with information. I do want there to be a bit of secretive to the theme, and not completely redundant in the communication, but Again I need it to be understandable easily. This esting for E4 has got so much going on but it works well because they happen at different times, and the last thing is the E4 logo, which sticks in your mind.