Since yesterday brands offering a poor mobile experience risk falling sharply down the Google search rankings. The update has earned the moniker “mobilegeddon” to reflect the far-reaching consequences it is likely to have for businesses that rely on online customers for their growth. A study by website TechCrunch found that 44% of the Fortune 500 companies in the US failed the mobile-friendly test. The BBC also confirmed today that sections of its own sites failed the test.