A logo is not a sales tool, it is used to identify your values and to build trust in your customer.
What is a logo?
A logo is a mark that identifies your business to your customers.
Don't use a logo to explain what you do
A logo does not work like a photograph or a banner or flyer, it does not need to hold masses of information.
Make it easy for people to remember you by keeping it simple. You should strive for quick recognition and identification.
e.g Adidas : Their logo doesn’t show that they sell sportswear, not a training shoe or t shirt in sight. It is a simple, elegant mark that has stood the test of time and immediately identifies their brand.