According to a recent Harris poll, the online seller edged out Apple, albeit barely. It's also the fifth consecutive year Amazon has been ranked as a "great" company.

So how does one define "reputable"?

Harris Interactive, the firm that conducted the study, lists six criteria: Financial performance, vision and leadership, social responsibility, emotional appeal, products and services and workplace environment.

The first criterion, financial performance, lists profitability and growth prospects as two factors that contribute to a good ranking. And while Amazon's profit margins aren't dazzling in the least, that's exactly what makes their growth prospects so appealing to investors.