On some sites, they give us the following options to click: pictures (quite obvious); or videos; tubes; clips... (what's the difference between these 3)?
I can't say I've heard the term 'Tube' being used, apart from on YouTube, but I would consider the difference between a Video & a Clip as being primarily length & detail. Take, for instance, a Porn Video. A video may be up to an hour long & involve the story of how they meet etc., resulting in the eventual rumpy-pumpy, whereas a Clip cuts in where the interesting stuff begins, and usually lasts, on average 8 - 10 mins - often, coincidentally, just the right amount of time for a reasonable masturbation session.