Interfaces should be compelling, and generally, intuitive.
I just saw an example of how not to do it – http://www.hasrimy.com/ – I draw your attention to the top right corner of the screen.
If you have to have something to explain a fundamental part of your interface – “scroll right for more” – it sort of says something about your interface. In particular it says, “I tried to be different but I’m so different, I have to tell you how to use me.”
It doesn’t, as a result, say “I’m easy to use.” and definitely doesn’t say, “I’m innovative.”
Yes… Intuitive is the word.
Wow, that website… BEST SITEZ EVAHZ!!!!!!!!11one
And indeed it took me about 10 seconds to notice the horizontal scrollbar.
Generally, a user won’t spend more than 10 seconds on a website if it has so little content.
I didn’t even notice the scrollbar until I saw the comment in the top right.
I should point out someone was directing me to the site to demonstrate how such a layout is actually effective, after they were asking me how to make a mouse scrollwheel scroll left/right… to which I refused, since to me that’s like asking a pencil how to write in ink.