Hi, Could anyone tell me what are difference between Apps, mobile site, Jquery mobile, and fluid grid layout. If I want to update my web design skills, which one should I learn? I am wondering if fluid grid design can solved design for multi device problem, do we still need to learn query mobile or mobile site design. I am very interested in learning app design, but not sure about what are the advantage for an online shop app over a mobile site? for example, Argos has an app published, what is better than viewing their website on mobile if the site is fluid grid layout design. And another question is hoe app store its data? I am intent to improve the company site I have designed a few years ago, to suit multi devices, it is a online shop, could anyone tell me which direction should I go for?