Responsive web design is a huge deal. So big, in fact, just about every tech, marketing, design conference out there has at the very least one session on responsive design.But what exactly is it? What makes responsive such a big deal? And why do you need to know what it is?
Responsive web design is that which adapts to its environment.
When speaker / web designer Brad Frost talks on responsive design, he always starts off his talks with these three images:


The web is no longer a desktop computer with a fixed resolution. Nearly every electronic device we use today is now connected to the web. And nearly every device is being used by somebody to visit your website.
One might say to themselves, “only five percent of my users view my website on a mobile device. Do I really need to cater to their needs?”.
Yes.
This website that you are viewing right now will deliver to you the exact same content in a slightly different form, adapting to each device used. It is being done with only one CSS file.
You would be downright stupid not to. That five percent that visited your website just had an awful experience. And they will do just fine not ever returning to your site again, or worse, tell others how horrible their viewing experience was.
So why is responsive web design the answer? Let me explain this to you first. This website that you are viewing right now will deliver to you the exact same content in a slightly different form, adapting to each device used. It is being done with only one CSS file. I’m no longer catering to mobile users, tablet users, PSVita users – responsive web design principles have allowed me to create the exact same experience for each of my users, no matter what device they’re on.
The best part for me as a developer though, is that I have only one file to update. No longer do I have to waste time updating a “mobile” or “tablet” version. No time wasted, and we all know time is money.
Is it completely wrong to have a separate mobile site? No, not necessarily. Quite frankly, your users could not give a flying flip whether your website adapts to a hundred different devices. What users do care about is that they can find the content they are looking for on your website no matter what device they are on. Sure, you can make a separate mobile site, but you better make sure it has all the same content as your regular website.
It is time that developers and designers move in a direction that is future friendly. It is time that we consider how many different types of devices are connected to the web and we fully support each and every one of them. It is time to adapt and respond.
For more info on what responsive web design is and how you can start using it in your code today, check out some of these awesome links: