Z80 Inside@ploum Google did a similar thing to Usenet. They ostensibly created Google Groups to be the world's most complete Usenet archive. Then they bolted on their own proprietary discussion group system, so it wasn't clear which groups were part of Usenet and which were just part of Google. Search degraded, with functionality going missing and some articles apparently becoming entirely impossible to access. At some point they stopped adding newly-created Usenet groups to their archive...
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