All of my original work offsite (I can't do it with my fanfic and have never thought about it for my LW posts, which I always assumed would remain under regular copyright by default) is under CC-BY-NC-SA. I'm happy to formally extend that to my LW posts, but I imagine Castify would find that unsatisfactory/unusable. I'm actually really uncomfortable with people making money off things I wrote without working out a deal with me. It certainly doesn't help that I'm kinda averse to audio content and don't want to check Castify's work to see if it's something I'm happy to have associated with me with this extra level of sorta-endorsement (extending a less restrictive license to the content that happens to interest them).