The recent years have seen the emergence and proliferation of online platforms that serve as an intermediation to connect demand and supply, ranging from business-to-business (B2B) platforms connecting buyers and sellers to peer-to-peer labor platforms connecting customers and service providers in the gig economy. With the advancement of digital technologies, online platforms are superior in their capability to match demand and supply more accurately, economically, and timely. In this dissertation, I study the design of such platforms with a focus on data-driven decision making, operational efficiency, and economics in Chapter 1 and 2. The evolution of the financial market has placed a profound influence on firms. Information asymmetry exists between firms and the investors in the financial market, and managerial short-termism has reported become more phenomenal in firms today. In Chapter 3, I study the impact of managerial short-termism on firms' operational decisions and long-term value. The titles of the three chapters of this dissertation are: (1) Chapter 1: Personalized Recommendation System Design for an Online B2B Platform; (2) Chapter 2: Bonus Competition in the Gig Economy; (3) Chapter 3: Operational Distortion: Compound Effects of Short-termism and Competition. Chapter 1 is joint work with Professor Vishal Gaur. Chapter 2 is joint work with Professor Li Chen and Professor Yao Cui. Chapter 3 is joint work with Professor William Schmidt. This dissertation explores a suite of methodologies including data-driven predictive models, econometrics, and game theory.Chapter 1 develops a data-driven algorithm to design a recommendation system for an online B2B platform and tests its performance in a field experiment. Chapter 2 adopts a Hotelling framework to investigate the pricing strategies of competing labor platforms in the gig economy and their impact on market shares, platform profits, and social welfare. Chapter 3 constructs a signaling game model to examine the impact of managerial short-termism on firms' operational distortion and long-term profits in a competitive environment.