To answer your question, which is a good one, I generally cannot read fanfic while I'm writing fanfic, for fear of being influenced by what I'm reading. Even if I'm reading in a fandom different from the one in which I'm writing, I worry that something (a trope, for example) will carry over without my noticing. I'll still read original fic, of course, but even there, I'm careful sometimes about what genre I choose. That's also the case if I'm *writing* original fic. I can read all the fanfic I'd like, but I'm careful about what books I'm reading while I'm writing, for example, the ambush project, which is a time travel novel. I won't read time travel stories while I'm working on my own. I'm just super impressionable and figure it's better to be safe than sorry. Good question, btw! :-)