(CNN) -- Sure, serious-minded folks from the White House on down have taken to Tumblr, the popular blogging platform that Yahoo announced it had purchased this week. When you host 105 million blogs, you're bound to have all types. But since hitting the Web in 2007, the blogs that have emerged as hits on Tumblr have tended to be silly, snarky or both. Photos: Big acquisitions in the tech world With its quick and easy tools for posting and image-friendly layouts, Tumblr has become a natural landing spot for folks in the entertain-me-now world of the Web. CNNMoney: Tumblr's David Karp on Marissa Mayer and dropping out of school
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On Tumblr, the random and humorous win the day
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Top blogs include pictures of kids crying for silly reasons, actresses with no teeth
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"Humans of New York" is more poignant, creating a sort of photo census
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Then there's a coloring and activity book -- of rappers
If most of these are silly, @placeholder is captivating and, at times, poignant.