A logo is not brand, nor is it your identity. Logo design, identity design and branding all have different roles, that together, form a perceived image for a business or product.
Here you have more information about then:
- Identity design
- Logo design
Then, these three concept are the base of marketing of the product or company.
In this interesting blog you can read more about this topic: http://justcreative.com/2010/04/06/branding-identity-logo-design-explained/