Brand identity is a big word for your logo. People can get obsessed with their logos but many people are looking for a steal. A great logo will last the company decades and become iconic. A bad one will become wallpaper. The following article clarifies what not to do with your logo. I applaud this article for making it so simple to say yes to good design without being snobbish about it. I cringe when I see these mistakes in practice but hope that the democratization of design will result in more lil' guys getting design (not decoration) to work hard for them.
http://tinyurl.com/logomistakes