I've had many different professional lives. For some inexplicable reason it seems that, just as I start to get good at something, I quit and start something else. This has had the unintended consequence of making me familiar with many different subject areas.
I generally restrict my edits to subjects in which I have direct first-hand knowledge and/or a reasonably deep understanding, and I also try to keep a light touch. However, I'm always open to suggestions and different perspectives.
A few areas in which I am interested and consider myself reasonably knowledgeable:
Software Development
Physics
The workings of the U.S. government
with the last being less of an interest and more of an unfortunate area of expertise.