The concept of Mobilegeddon emerged to mark April 21, 2015, the date on which Google was expected to potentially favor mobile-friendly sites in its search results displayed on mobile devices. This term was chosen to illustrate the feared impact on the rankings of sites deemed non-compliant. However, the much-feared Mobilegeddon of spring 2015 did not have the expected devastating effect, and the consequences of non-compliance remained limited.

The notion of mobile compatibility goes beyond the simple responsiveness of a website and can be assessed using the Mobile-Friendly Test tool provided by Google. In 2018, a second Mobilegeddon was announced, this time related to the transition to an index that prioritizes mobile versions of websites. It is therefore crucial for websites to comply with mobile-friendly standards to maintain their visibility and ranking in search results.