The post highlights two open-source applications created by Nicolas Grenié that connect popular services with Slack chat using Fauna as the database. The Stack Overflow Monitor posts messages to a Slack channel when new questions match specific search terms, while Glitch Notifier alerts users in a Slack channel when new questions are available on Glitch. Both applications utilize Fauna's features, including serverless architecture and transactional capabilities. The code for these applications is publicly available, providing a starting point for developers to create their own apps using Fauna.