In Selenium testing, synchronization is a common problem that can be solved using various techniques. With the shift from Web 1.0 to Web 2.0, clicking a link no longer guarantees a page load due to AJAX's asynchronous nature. As a result, developers use `waitForPageToLoad` and its variants in older browsers or `isElementPresent`, `isVisible`, and `available` conditions in newer browsers. However, when dealing with complex AJAX interactions, the `latch` technique is employed as a synchronization method of last resort. This involves setting a value in the browser's DOM that is monitored by the script for synchronization, such as the `window.latch` variable in Ruby on Rails. The `waitForCondition` command can then be used to wait for this condition being met, allowing developers to automate complex interactions with Web 2.0 applications.