Matthew Casperson's article discusses a method for conducting UI tests on applications post-deployment using Octopus and AWS. During the NDC conference in Sydney, a question arose about running tests against previous deployments without them being part of the deployment process. The article provides a detailed walkthrough of deploying a CloudFormation template to AWS, creating an EC2 instance running Tomcat, and saving the public IP address as a variable in Octopus. This variable can be used later for UI tests by creating a separate Octopus project that utilizes a PowerShell script to access deployment details and perform network tests. Casperson highlights the flexibility of running these tests in any environment and suggests enhancements like using worker pools for international testing, scheduled triggers for automation, and notifications for error reporting.