3 genres Textbooks, Texting, and Advertisement

When I am reading a textbook I am looking to understand the information and go in depth. I read textbooks for school strictly and would never touch them if I wasn't learning from them. But when I read text message I imagine the conversation.  Then I quickly think of a response and send it. And just wait for another text. You have to wait for the information to come, but for textbooks and advertisements its all right in front of you. Advertisements are a whole different thing. When I read an advertisement I read it out of bordom and think about whether I need this product or not.  I read all types in different ways and its hard to read a textbook like a text message, or a advertisement like a textbook.  That just doesn't happen. These three genres are all very different in my mind and they rarely mix.