That's really cool, Steph! Has fanfic influenced anyone else's life or career in some way?
For me, as a teacher, writing as a hobby has not only made me a better writer, but also a better teacher of writing. The writing I do in front of my students to model different strategies is probably stronger than it would have been if I hadn't gotten into fanfic, at least when it comes to fiction/narrative writing. And just having a love of writing makes it more fun to teach, too.
Also, going along with the HTML thing, running my own website for so long has taught me lots of technology skills that have come in handy in my career and real life - building a website, creating graphics, using social media, etc.