Type of Logos

In Graphic Design class I have been learning about the different types of logos like abstract, representational, and font based.

Abstract logos are logos that don't actually represent the company, like
Nike, MSN, Apple, and Shell (Gas Station)

Representational logos are logos that represents what the company does, like,

Burger King

Font Based are logos that are strictly font based, like,

IMB, T-Mobile, and HBO