The document discusses the paradoxes of big data. It notes that while data volumes are large, useful data can still be refined to fit in memory. It also discusses how the ecosystem around big data technologies like Hadoop and Spark has grown rapidly with many startups receiving funding. Practical uses of big data involve using tools like Dataiku's Data Science Studio to clean, model, and extract insights from multiple data sources to optimize processes like deliveries or improve search relevance. The document provides steps to get started with big data including learning Python/R and practicing on platforms like Kaggle to enter the field.