What makes an effective logo? Well, a logo is any kind of image that communicates a message to an audience. Logos are typically used to represent some kind of organization or group. Logos can be both extremely effective or very unproductive. Below, are an example of each:
This is the logo for the Portland (Oregon) Trail Blazers NBA (National Basketball Association) team. This logo features stripes, in red and gray, that join together in the center to form a circle. Although a fairly nice design in itself, this logo, in my opinion, is quite ineffective. Firstly, and most importantly, this symbol in no way represents the Portland Trail Blazers or basketball directly. Secondly, the colors are dull and do not quickly capture your eye. Although I believe it's a stretch, I suppose the circle could be a representation of a basketball and the ends of the stripes a way of indicating that it is moving quickly. However, this is just my interpretation and I still believe any message that an organization is trying to communicate through a logo should be readily decipherable.
This is the logo for the corporation Target. Target is an American retail company featuring a variety of products from electronics to clothing. I believe this is an example of a highly successful logo. Excluding the name printed below, the main feature of this logo is the red bulls-eye (target). The designs readily draws in your eye with the bright red color. The simplicity of the logo also communicates easily the name of the store as well as the fact that the store is a "target" for all of a customer's needs. Target's logo is a prime example of clearness and effectiveness needed to create an outstanding logo.