The talk describes open source tools that enable search on streams: Luwak is a Lucene-based library for running many thousands of queries over a single document, with optimizations that make this process efficient. Samza is a stream processing framework based on Kafka, allowing real-time computations to be distributed across a cluster of machines. The speaker discusses how these tools can be combined into an efficient and scalable streaming search engine, and how they can be used to build full-text search engines like those found in Twitter and Google Alerts, with optimizations such as indexing queries and partitioning streams to enable scaling and performance.