CIOs face challenges in deciding whether to buy or build big data solutions due to the ambiguity of the term 'big data' and inadequacies in vendor offerings. The discussion at a recent symposium highlighted the trend towards customized solutions, as seen with Tesla's decision to build its own ERP system, suggesting a shift from all-encompassing vendor solutions to more tailored approaches. Experts recommend focusing on specific business needs and outcomes rather than relying on blanket technology solutions, emphasizing the importance of understanding the technical requirements closely linked to business problems.