This document discusses the importance of collecting the right data to understand a web business and customer interactions. It identifies several main types of data that can help improve a website, including behavioral data from web analytics to understand site traffic patterns, attitudinal data from surveys to understand customer motivations, and competitive data from third parties to establish goals and understand demographics. Secondary data sources mentioned include call center data, customer data from registrations and transactions, third-party research reports, usability testing, heuristic evaluations, and community sourced data.