A primer for entrepreneurs.
A logo is so much more than a name and/or an icon. It’s the central component of a larger idea, your “visual identity.”
Wikidpedia has an interesting section on the cultural aspects of a visual identity.
Organizations with more than one person who communicates with the outside (and isn’t that any organization with more than one staffer?) need to ensure consistency in what they send out. Thus, along with a logo, you may need a “branding style guide.” It includes visual presentation, and sometimes includes copywriting guidelines — even the “tone of voice” for your communications. Smashing Magazine outlines the basic components here.