A logo is also a trademark or brand. A trademark is a legal commercial mark that may not be used but by only the company that registered and paid for it. Anyone else using it or copying it may be liable for fraud proceedings. All kinds of organisations own logos especially commercial ones, but also institutions of learning. Examples include Michigan state university, university of Washington, Virginia, Illinois, university of Michigan. Also do not forget the university of Maryland, Florida and university of Arizona all have logos.
Logos covers a range of various graphics that may include emblems, coat of arms and flags and is not limited to commercial purposes only. But it is the commercial ones that come to mind more easily. Coca cola is associated with the red colour and Pepsi with blue, and it’s easy to find out just look on their home page. Other famous logos include Nike,Fila,FedEx and UPS.
Logos are important in international trade as they are easily recognised unlike if they had to be translated into the local language and hence losing the original meaning and brand recognition.