[bq="WhoovesHoovesDoctor"] I would like to know what the "great exodus" was. [/bq]
Once upon a time, there was a website called Ponibooru, created by the great Eco. For a while (2011), it was good.
But as the fandom grew in size, so did Ponibooru's technical difficulties and downtimes. Eco couldn't hande it. Then the moderation stopped almost completely. In mere months, the once serene place turned into an open sewer.
Finally, in June 2012, Eco closed the place down without a warning. In his last communication to us, he directed us here, to Derpibooru. And we came. Ponibooru was no more.
That's the brief history of pony boorus.