In the past, the standard approach to a mobile web site was to create separate simple pages for a small screen. Very often, functionality from the main site was dropped, as was much of the content. Maintaining two separate sites was time-consuming, and with fewer users on mobile devices, the compromise was generally to downscale for the mobile version.
The Foundation responsive framework provides functionality to enable a web page to reformat dynamically for different screen sizes, and to add features for touch screens. This way, your full site is accessible via mobile, and you don't need to maintain separate versions of content for both, or update and fix two sets of code.
Foundation also provides mobile-friendly features that can easily be integrated into pages such as slideshows, modal popups, lightboxes and various menu systems.
If you are looking to build an e-commerce web site, our Kartris system integrates Foundation, providing a mobile-friendly web site capable of handling anything from a small boutique site to a huge b2b supplier with over a million product lines.