Instagram wants more teens. So it went looking for them on YouTube.

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• Meta and Google are serious competitors.
• But they can also do business together: Turns out Meta's Instagram was buying ads, targeting teens, on Google's YouTube.
• There are questions about whether that campaign was legit. But as far as giving your rival money to help build your own business? That seems pretty standard.

Instagram is huge. But Mark Zuckerberg would like it to be bigger...