That's what I figured. I do see that Hurricane Electric, which is directly peered with Serious Tubes, still has a valid route there...making me think that 194.71.107.0/24 is still being announced at the source.

thepiratebay.se resolves to 194.71.107.15 for me. Looking at our routing tables, we aren't seeing routes from our upstreams for a block that contains this address.