The document discusses Marketo's efforts to rebuild its web tracking infrastructure to greatly increase its capabilities and scale. The legacy system could only handle 2 million activities per day and had problems with delays and lack of flexibility. The new Orion initiative aims to support billions of daily activities with near real-time processing using a distributed architecture with Apache Spark, Kafka, and HBase on Hadoop. The initial results included supporting a key customer's increase from 2 million to over 20 million activities per day with latencies under 30 seconds.