Thank you guys for your insights. I think I may not have explained clearly enough what I meant. I don't mean links related to the video (for example all links in a series) or social networks, etc. What I meant was links that are unrelated to the particular video, but that are from the same channel or about the same subject (toys). For example, I took the links below from a very popular channel video description to give you guys a clearer idea of what I'm talking about. If the user was merely describing the video's content, they wouldn't be able to stuff all these keywords in it, some of them you could even call tags.
There are just SOOOO many keywords in here that wouldn't be there if the user had just described the video content because the video is not about all these other toys (the video is actually about a giant Hershey bar). So this is a perfect strategy to rank this video for all these keywords (assuming the video is performing well in other aspects, too, like audience retention, etc). So if the video is performing well in all the other areas that the algo takes into account, having all these keywords is going to give this particular video a huge boost in rankings for all these other toys, even though the video itself is not about these other toys.
Of course if the video is doing poorly in other algo signals such as audience retention, they can have as many links as they want, the video won't perform well. BUT if it does, then they're not only going to rank for "giant hershey chocolate" (the video's actual content) they are going to rank for Teenage Mutant Ninja Turtles, Thomas the Tank Engine, Gummy Candy, Spiderman, Superman, Surprise Eggs, Disney Cars, Lighting McQueen, etc. So if the user was going to get 100,000 views because of good rankings for Hershey chocolates and candy, now this user is going to get 1,000,000 views because he didn't limit the keywords in the description to candy or chocolates. Therefore, he's also going to rank for all these other keywords, because now YT "thinks" this video is about all these other things. And since the video is good, someone that was looking for Batman and gets this video in the suggested videos, might feel curious and decides he wants to watch a video on Hershey's chocolate instead of Batman. So YT's algo keeps "thinking" the video is relevant to Batman, etc.
We could say this kind of strategy goes against the YT guideline that states "Do not include metadata in your video that is not directly related to your video."
Or would it be related in the sense that all these other toy keywords are things children like just as much as they like candy??? So therefore, "Batman" and "Spiderman" is perfectly relevant to "Hershey's Chocolate Bar"????
My channel manager thinks this falls under spam and he says if I do it my channel might be at risk if a really conservative YT moderator happens to see it. However, so many huge channels are doing it and I really believe this strategy is giving them that insane boost they're getting. I think we all work hard to grow our channels and if they're allowed to do this, everyone else (even if they are smaller) should be able to get the same chance.
World's Largest Gummy Candy Challenge and Fun with Food and Candy Challenge playlist
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WORLD'S LARGEST GUMMY SNAKE CANDY CHALLENGE 26lb Giant Gummy Worm Python (channel name)
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World's Largest Gummy Bear Challenge (channel name)
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WORLD'S LARGEST GUMMY WORM CHALLENGE (channel name)
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GUMMY JOKER TONGUE Viper Tongue Gummy Pizza Marvel Egg Surprise Toy Candy Review (channel name)
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PIE FACE SHOWDOWN CHALLENGE NEW Whipped Cream in the face Family Fun game for Kids Egg Surprise Toys
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ICE CREAM MAKER Cra-Z-Art The Real 2 in 1 Ice Cream Machine Toy for Kids (channel name)
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Snoopy Snow Cone Maker Machine from The Peanuts Movie Toy for Kids (channel name)
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Teenage Mutant Ninja Turtles Pizza Oven Toys For Kids Family Fun Activity (channel name)
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The Real Cotton Candy Maker with Lite Up wand toy for kids (channel name)
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Chocolate Candy Make Your Own Japanese Candy For Kids Bear Bunny Egg Family Fun Toy (channel name)
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EASTER EGGS Surprise Toys Challenge Disney Cars Toys Paw Patrol Batman Superman Thomas and Friends
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SURPRISE TOYS GIANT BALLOON POP CHALLENGE Batman vs Superman Disney Cars Toys Thomas and Friends
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Part 1: Unboxing
GIANT INFLATABLE SLIDE for kids Little Tikes 2 in 1 Wet 'n Dry Bounce Children play center
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Part 2:
HUGE EGGS SURPRISE TOYS CHALLENGE Inflatable water slide Disney Cars Toys Paw Patrol Spiderman
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McDonald Indoor Playground for kid Happy Meal Surprise Toys Transformers (channel name)
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McDonald Indoor Playground for Kids Happy Meal Surprise Toys Shopkins Rabbids (channel name)
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Disney Cars Toys Lightning McQueen Tow Mater Playlist
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Disney Cars Lightning McQueen Scooter Shopping Trip with (channel name)
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Family Fun Adventures Amusement Park Outdoor and Indoor playtime Playlist
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THOMAS AND FRIENDS Train Rides for kids Thomas Land Edaville USA amusement park (channel name)
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GIANT THOMAS AND FRIENDS kids Train rides Thomas Land Edaville USA amusement park (channel name)
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HUGE Indoor playground GIANT INFLATABLE SLIDES and Bounce House for kids play center (channel name)
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GIANT LEGO World's biggest indoor playground LegoLand Discovery Center kids Video (channel name)
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Chuck E Cheese Family Fun Indoor Games and Activities for Kids Children Play Area (channel name)
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Indoor Playground Family Fun Play Area for kids Giant inflatable Slides Children Play Center
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Family Fun Indoor Games and Activities for kids Main Event Entertainment Fruit ninja Cars Racing
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Indoor Playground Family Fun Play Center for Kids Giant Inflatable Slides Children Play Area
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