I am not sure if you have noticed, by Twitter has implemented what I would call a very innovative use of responsive web design. Responsive web design is where a website uses the same web design, but literally “changes” in a way that it looks good in any sized web browser–even on a tablet or smart phone.
In the case of Twitter, you can see what I call an innovative use of responsive web design when you resize your web browser. If your browser is more of a “normal” size, meaning that it takes up most of your desktop monitor’s screen, then it will look like this in the top left:
But, if you resize your web browser to make it smaller, you’ll see this:
Notice the difference between the two?
In the larger version, you’ll see the full words “Home, Notifications, Messages” and their icons. But, if your screen is smaller, then it will switch, automatically, to an icon-only view.
Twitter has a mobile version, which is different than the mobile version which is quite smaller than the desktop version. For example, the mobile version on my iPhone on Safari (not the app) looks like this:
Responsive web design is important, as visitors are using smaller and smaller screens than we used before, such as smart phones and tablets. And the search engines, as well, are realizing that. Take a look at your site using various devices to access your site (mobile, tablet, and desktop) and make sure that your site’s able to adapt to the user’s screen size.