When I was young my great-grandfather started a tanning business, in the sense that he was a tanner who produced leather goods. He had to buy a sign to put above his shop. The sign maker asked him if he wanted to put a logo on the sign, too. "Why?" asked my grandfather. "So people will recognize your business," said the sign maker. "That's what the name is for," answered grandfather. Even at the time I thought this w…
Logos seem more important in the physical realm than the digital one. Great for advertizing on Bilbords, shirts, TV etc but meaningless when the goal is to click the link not remember the company.
More than logos, you need consistent and recognisable look and feel to an advert. This way the companies presence is communicated at a glace, which is what most people offer to digital ads.