Evernote's elephant logo is similar. Elephants, like Evernote's cloud notebook, never forget. A ghost, like Snapchat's "Ghostface Chillah" icon, disappears just like Snapchat's photo messages.

Designing a logo can open a company up to a lot of praise or criticism. When Marissa Mayer unveiled Yahoo's latest logo, for example, the Internet exploded and said it was "boring." Tumblr pages ...