I suspect it is another example of Google maximizing data that is available to them. They already index SDMB at a near-instant rate. It isn’t a stretch to imagine they can scan for videos referenced and collect them in one web page.
Yeah, it’s interesting. Using Google image search, I often find images which, when moused over, reference the SDMB as the site they are on. Because someone referenced the image in a post, the image becomes forever associated with SDMB in Google results. This could be good or bad I suppose.