Responsive Web Design
Responsive web design is a very important aspect of web design today because everyone is moving on from their pc’s as our mobile phones are getting more powerful. Sooner or later, we could ditch the whole desktop thing, or web design will go through another phase (which is bound to happen).
Responsive web design is responding to the devices resolution
How to achieve it?
Making <div> containers for your content and setting a defined width is a good way of keeping the resolution and making it responsive throughout the sizes.
Using percentages and max widths are also a good way to make it responsive.
Here is a video on responsive web design and how to do it properly. Very good video, definitely worth a watch.
Pros and cons
better for everyone
One single website
technical side ( a bit harder to learn )
A single website (you may need to change some things to retain for the mobile users)
In instances, data for mobile phones should be considered as well as using adaptive or responsive for either. Being careful, i think any of these choices should be made respectively and intuitively. You could also create an app to prevent the loss of data on peoples phones, because you could be losing customers.