"Clarity helps to reinforce your concept and guide readers through your advertisement. Nothing is more pleasing to a potential buyer than a clear presentation of your message, simple statements of benefits and straightforward information on where and how to buy."

Clarity = clean presentation of your ideas

Clarity will reinforce your sales message. Visitors will appreciate the clear presentation of your message - simple statements of benefits and straightforward info on where & how to buy / learn more.

Clear layouts:

• make order out of the components of your advertising message
• clearly communicate your message
• encourage easy scanning

Some of the tools used to achieve visibility--a strong single illustration and large headlines-- also simplify and clarify your message.

Source: http://www.conestogac.on.ca/~sfinlay/supplemental/design.html