One of the big lessons I picked up from the marketing books of Al Ries and Jack Trout -- "Positioning: The Battle for Your Mind," "Marketing Warfare," "The 22 Immutable Laws of Marketing," and several others -- is the importance of having a color associated with your brand.
A great example is the world of rent-a-cars. The original leading firm in the space, Hertz, has used yellow (with black highlights) for decades. The "#2" firm (and I'm using quotation marks because they're actually #3, but their marketing angle is that they're #2 (so they try harder)) is Avis, which picked red. National picked green -- and aggressively and effectively features it in its marketing. Next, Budget: Orange (with blue). Less effectively, Thrifty and Alamo went after blue, the former with white highlights and the latter with yellow highlights. Dollar is not very well-positioned in my mind, but maybe that's because they use all three primary colors (along with black), which is not very memorable.
Off-pattern is Enterprise, which is actually nowadays the #1 firm, because it focused on a different target market (the insurance replacement vehicle market) and also uses green. I'm thinking that since they were entering a new market, any color would work, and "green," being associated with money, works in that context. But maybe I'm rationalizing.
Let's look at the world of Internet radio: Pandora owns blue. Slacker has gone for black-and-gold. Last.fm is red. I Heart Radio has also selected red, but their listeners are presumably pretty mainstream, so they may not be familiar with the hipster brand of Last.fm (and vice versa). Regarding AccuRadio, we're really not practicing what I am preaching: We were khaki in the early 2000s, then switched to blue (with yellow highlights) prior to Pandora's arrival on the scene, and now are vacillating between blue and (on our iOS apps) maroon.
At any rate, to quote Ries & Trout: Picking a corporate color for your brand can be an effective marketing tool.