What Is a Mobile Website?
We all know what a website is ... but what makes it "mobile"? Put simply, it is a website that is optimized for viewing on a smaller resolution screen—like the ones you find on mobile devices. If you try to cram a full sized website onto a mobile phone screen, for example, the users have to zoom in and out and move all around to get where they want. A mobile website will have everything laid out nicely so you can easily scroll to find things and links are easy to click.
Pros and Cons of a Mobile Website
A mobile website can typically be brought to market quicker because you don't need to submit it to the app stores for approval and it is developed using widely familiar HTML and CSS languages. Another advantage is that if you build a mobile website once, it can run on nearly all devices with no additional work required (assuming you stick to proper W3C standards). With the emergence of HTML5, the mobile website is more powerful than ever. It can now access nearly all advanced features of mobile devices, like the accelerometer to see if the device is being tilted, and the GPS to see where the device is currently.
One important advantage in choosing a mobile website is that you can always build a native app that "wraps" the mobile website and simply displays the screens you've already built. This is a less expensive variant of building a customized native app and it gets you a place in the app store.
The disadvantage of the mobile website is that you cannot take full advantage of advanced UI features available on the native device, and you don't get priority access to the CPU—so if you want to do something CPU-intensive, a mobile website is not currently the best choice.