I saw this on the /r/LearnJapanese subreddit yesterday, and it seems like something that could be really useful. Type any Japanese word or phrase into the search bar, and it will return a list of YouTube videos containing that word in its Japanese subtitles. It also starts the video shortly before the word is spoken, so that you can listen to it in context.
(I assume that it also filters it so that it only lists videos that have marked Japanese as the audio language, but I’m not certain.)
I think this could prove quite useful both for listening practice and for finding native example sentences.