The Common Craft video on Plagiarism was being tweeted a lot a couple of days ago, so I checked out their site again. You will probably know that they developed a style for explaining technological apps etc (e.g. wikis, Twitter) using paper cutouts and plain English, in short videos.
1) It did not seem straightforward to identify exactly when each video was made (and they haven't updated their Youtube channel for a while, I think to drive traffic to their own site). However, trawling through their news blog, the Plagiarism video was released in October 2011. More recently they have produced ones on Crowdsourcing, Cookies and Apps.
2) Some of the videos are available in 8 other languages e.g. Spanish, German, Japanese. To go to the sites in other languages, click on national flags at the top of the main website : http://www.commoncraft.com/
3) The art of explanation is a forthcoming book by Common Craft's Lee LeFever, which should be worth checking out. It has its own website at http://artofexplanation.com/, but there is not anything much there at time of writing, and the posts about its progress are on the Common Craft Blog.
4) One interesting blog post by Lee LeFever is 5 Trends Behind the Growing Shift to Video Explanations. I realise, myself, that I'm doing more and more short explanatory videos e.g. I made short video recordings to explain to my students how to get to unfamiliar rooms (like this one, one on how to fill in our research ethics application form (etc. etc.) LeFever finishes by saying "We could be at the beginning of a wave that will change how we think about the role of video in helping people feel more confident and informed in the face of a rapidly changing landscape. Perhaps soon we’ll see that the genres of video have a new and productive member. Drama, comedy, documentary, advertising and explanation."