Ryosuke Matsumura gave a presentation on using Application Insights to aggregate logs from a Rails application. He began by introducing Application Insights and its capabilities for monitoring apps and collecting telemetry. Next, he discussed why it is important to aggregate logs, such as for analyzing errors and performance. Finally, he demonstrated how to set up Application Insights for a Rails app by adding the required gem, configuring the instrumentation key, and using the telemetry client to track events and exceptions. The presentation concluded with a live demo of Application Insights monitoring a Rails application.