Responsive Design is a shift in how we build our sites. Starting from a mobile first perspective. By leveraging proportion based grids such as those in the newest build of Twitter Bootstrap, flexible images and CSS3 media queries our site can adapt to any device and still look great doing it.
Media Queries allow us to provide different styles to different devices. Where once we provided separate logic for every device, we can now target mobile first an adapt to a richer experience. A simple media query will define a min and a max width in which to execute its styles.
media="screen and (min-width: 401px) and (max-width: 600px)"
With these we can progressively define how our site will display using various screen sizes. A good way to get starting using responsive design is to get the latest copy of Bootstrap. From a fluid grid system to responsive images to predefined media queries this framework is a excellent way to get up and running using some of the latest practices.
WebSockets have given rise to some impressive libraries and frameworks. Some libraries worth mentioning are socket.io and signalr. Frameworks to keep any eye on are Meteor and Derby. It will be interesting to see how these libraries and frameworks impact the web and our definition of what it means to real time.
RESTful web servies give us a simple way to reach clients from internet browsers to mobile devices. Leveraging RESTful web services you can provide reusable APIs that are easily consumed.
Its never been easier to find the right tool for the job.