Why It Matters
More than half of all web traffic now comes from mobile devices, and for many local businesses the figure is significantly higher. Google uses mobile-first indexing, which means it primarily looks at the mobile version of your site when deciding how to rank it. If your site is difficult to use on a phone (tiny text, buttons too close together, slow loading over mobile data), visitors will leave and Google will take notice. Beyond rankings, mobile experience directly affects conversions. People searching on their phones often have immediate intent: they want to call, get directions, or make a quick purchase. If your site makes that difficult, they will move on to a competitor whose site does not.
Example
A restaurant’s website looks impressive on a desktop but is nearly unusable on a phone. The menu is a PDF that requires pinching and zooming, the reservation form has fields too small to tap accurately, and the page takes eight seconds to load over 4G. After a mobile optimisation project that replaced the PDF with a responsive HTML menu, enlarged form fields, and compressed images, the mobile bounce rate drops by 40 percent and online reservations increase by a quarter.
Mobile optimisation overlaps closely with responsive design and has a direct bearing on Core Web Vitals scores. Both are in the glossary.
