So, to return to the original purpose of the thread. I think the potential that this combination of technologies provides is to improve the signal-to-noise ratio when using the available video clips for some particular purpose amongst the many different reasons that people had for posting them.
One such purpose is highlighting bad driving in an attempt to get some kind of change that might eventually improve the lot of cyclists on the road. There seem to be (at least) two potential ways to select videos for this purpose: repeat offenders (or at least vehicles that appear in more than one video), and selection based on the seriousness of the incident.
The "repeat offenders" one is probably a non-starter given the relatively small number of cyclists who post videos. I spent a bit of time playing with the YouTube API and wrote a program that extracts registration numbers from the titles of all videos on a particular channel, does a search of YouTube for any other videos with the same registration number in the title, and then lists them under the registration number. I was not surprised to see that there are very few repeat offenders turned up, even for some of the London commuters' channels - Mikey and Gaz for example. (I had fun writing it, though.)
So that leaves the seriousness of the incident as a basis for selection. There are many videos that, whilst showing behaviour that undoubtedly causes increased risk to the cyclist, are subject to debate even among cyclists as to whether the behaviour was sufficiently dangerous to warrant highlighting. (You only need to look at this topic for proof of that assertion.) It seems to me that the best approach, then, is to "pick the low hanging fruit" and concentrate on videos showing incidents that leave little or nothing open to argument regarding whether the driver's behaviour was dangerous. (I know, there will always be some 'ard man who claims that a truck screaming past at 40mph three inches from their elbow is nothing to make a fuss of, but I think we can just ignore them.)
Earlier, I suggested that some standard for tagging videos might be useful to aid in this, and I do think that might serve a purpose if enough people starting tagging according to the standard. However, it seems like that may be a sledgehammer to crack a nut; I've been involved in standards-making in the past and getting agreement on even the most trivial detail can be a right pain.
So, for those that are interested, why don't we just each share links to a small number of videos that we think are extreme examples and make a page of them? No fancy searches, just people. If anyone doesn't want to join in, then they are quite free to remain silent.