The typography in this image is effective because of the way everything was positioned. They have the main text in bold and in a bigger font, and then everything else is a smaller font coming out of her head which emphasizes the message of the art.
The fonts used in this image are all sans serif (except for the fonts on “like” and “idea”, which is more aesthetically pleasing. They also kept it monochromatic which gave it a consistent colour scheme. Using a variety of different fonts makes it more visually interesting to look at.
This poster is for the movie Helvetica, and the poster uses only the helvetica font. It is effective because it emphasizes what the movie is about. They also used colour only on the text for the movie title, which creates contrast and emphasis. It is also a sans serif font.