Selenium, an open-source tool for automating web browsers, celebrates its 20th anniversary this year. The author reflects on their journey into test automation and how Selenium has played a significant role in the industry since its merger with WebDriver in 2009. They highlight Selenium's advantages over other tools, such as being free, open-source, having cross-browser support, and adhering to web standards. The author also mentions how Selenium has inspired the development of other automation tools like Playwright and Appium.