FurAffinity is so tightly coupled to the whole LAMP philosophy- all the rage in, oh I dunno, 2005 or so before everyone realized that PHP and MySQL are a bunch of garbage and don't scale. I haven't even seen the code and I can tell you there are SQL queries just randomly littered in the files everywhere, and then the code that renders the query results will probably break beyond all repair if you were to replace the query with even a different schema, let alone something like NoSQL.
Personally, I wonder if Yak will catch on to this "eventual consistency"* bullshit that Twitter uses, and when their caching shits the bed again, he'll claim it's a feature, and not a bug.
* If you've ever wondered why it takes eight zillion years for your Twitter followers' new icons to actually show up in your browser/client, well, there you go.