Part of the fun of playing dressup’s making up reasons though :P  
But I missed out on Moonstuck the first time around, and going back now (well, going ALL the way back after catching up from midway through) I’m impressed with the author’s willingness to run with suggestions.  
Pretty much all ask-blogs, CYOAs, or ‘homestuck-likes’ (whatever we wanna call those) have some pretty strict plots, and only take inspiration from messages and such.  
Moonstuck gives the impression the artist’d have Woona sit around doing nothing if there wasn’t the audience.
 
Heck, that’s rare ANYWHERE - even in roleplaying games, you usually only have so much freedom.  
Above all, I think it speaks well of their ability to improvise.