I was sitting here drinking with some friends the other night reminiscing on some of the old 90's songs we grew up with. We couldn't remember the exact song names or who they were by so we resorted to just typing in the lyrics to the catchy chorus hooks that we could barely remember. Thing is, the lyrics we were typing in were nowhere to be found within the description, title or tags of the video...Yet youtube knew what we were searching for and it would come up within the first couple results nearly every single time Four explanations we cooked up #1. closed captions and subtitles have the same search terms - many didn't have them #2. they could have been embedded on some music lyrics site or forum that had the phrase I was searching on the same page - could their search algorithm really be this intricate? #3. If a user searches for something, but the search doesn't return the results the user wants, then they will most likely not click on any videos at all and just go search another term in an attempt to find the video they were originally looking for... And if on their 2nd attempt they were to actually find and watch the video they were searching for the first time, the keywords from the 1st search would add more ranking power to the video the user found on their 2nd search attempt (even though it doesn't have the exact search term) maybe? - Should I be wearing a tin foil hat at this point? #4. comments - most of the videos had thousands of comments so finding someone mentioning/quoting the exact phrase we originally searched for is like finding a needle in a haystack...but this seems like the most reasonable explanation to me at this point.