Designers often encounter clients who don’t quite understand what goes into making the logo they ordered. This isn’t their fault, but a little bit of education in the beginning can help you avoid problems later. A common misconception is that a logo means a graphic of some kind, with or without text. But the truth is more complicated than that. There are many great examples of logos which are just text, though it's rare to see a logo that is just a symbol.
For example, here is Tiffany and Company:
The type, combined with their signature blue color is the whole logo. No mark at all, no graphics anywhere. But even though it’s just type, it’s still very much a logo. Just because it’s simple doesn’t mean it’s not a “real logo” and it certainly doesn’t mean that a great deal of time, energy, skill and talent didn’t go into making it.
Some logos have both type and symbols which work together to create a more complicated design.
The symbol in a logo is called the "logo mark" ("mark" for short) and is used in conjunction with type to create the complete logo for a brand.
In a good logo, these elements always work together, and are also instantly recognizable on their own. They’re a unified set, the type and the mark compliment each other.
Nike is a very famous example of mark and type working beautifully together, and also working by themselves to create an indelible brand even at its lowest common denominator.
Just the “Nike swoosh” on its own means “Nike.” Just the type (the word “NIKE”) still means “Nike.” Of course, they’re more potent together, but break them apart and they still retain the brand’s meaning.
A good logo should be simple, and clean, and work as well photocopied on cheap paper and faxed as it does in full color, blown up on the side of a building.
There are plenty of ways to add “flair” to a brand in subtle ways, and to get meaning across without doing anything complex, busy or loud.
There are also many famous examples where the mark is combined with the type in ingenious ways. The hidden arrow inside of FedEx expresses forward movement.
(See the arrow made from negative space in the second E and the X?)
The bear inside the Matterhorn in Toblerone represents the national animal of Switzerland, where the chocolate comes from.
(See the white dancing bear in the negative space of the mountain?)
A professionally designed logo is a key element to a proper brand. The best logos are evocative, memorable, and positively identified with the company they represent.