2. F5 Networks' ( FFIV) Application Delivery Controller (ADC) products help companies manage their computer network traffic more efficiently. It also has products that address security concerns. F5's customer base has evolved from an initial focus on Internet service providers, Web sites and e-commerce sites to the Fortune 500 corporate IT market. Its clients now include: Citigroup ( C) and General Motors ( GM). F5 is taking market share from bigger competitors such as Cisco Systems ( CSCO). In fiscal 2010, revenue grew 35% as operating margins expanded to 26.1% from 19.3%. Outlook: In the fourth quarter, revenue rose 45%, which bodes well for 2011 as the pace of revenue growth increased throughout the year. Analysts' consensus five-year annualized earnings growth forecast is 23.5%, roughly double that of the S&P 500. Analysts give the company mixed reviews, with 14 rating it "buy," two "outperform" and one "sell," according to FactSet.