4. EquinixEquinix ( EQIX), like Digital Realty, is a data center company that counts Facebook among its customers. In addition to Facebook, it has customers in financial services and data networking. The Redwood City, Calif.-based company recently posted strong first-quarter earnings and revenue that jumped 25% year-over-year as its cloud computing, mobility and data management businesses grew at healthy paces. Equinix reported earnings of 71 cents per share on $452.2 million in revenue. Wall Street analysts polled by Thomson Reuters were looking for 49 cents per share on $445.1 million in revenue. Equinix also raised its second-quarter and full-year revenue forecasts. Shares of Equinix have gained 55.17% this year.