Looking at the cc site on my iphone right now, and am trying to watch the Form Builder slideshow. When clicking the start button, I get redirected to Vimeo, and there is a black label with three options on the right, two of which I'm able to see when holding the phone in 'landscape' position. The third one is below the view port, and this black label can't be scrolled.
Since I don't know vimeo, I wouldn't know if I 'like' it or not, and as a consequence, I can't watch the Form Builder slideshow. Looks like I have to register with vimeo to have access to the slide show, but I get enough spam as it is, so I'm not particularly thrilled about giving them my mail address.
That could be just an issue with your iPhone or possibly your regional settings. I tested it on my iPhone and Tablet and it plays right in my browser never taking me to Vimeo. We would never post videos on our site that force you to signup with a 3rd party service.
Here is what I see: