1) How much of the character's backstory did you know when you started to play them?

Not a great deal. There are the odd titbits in the series that I missed the first time round and there's quite a bit in a couple of the books (mostly the one that Ian Marter wrote), but I hadn't read them then. So he was pretty much a blank slate.

2) How specific or vague do you tend to make a character's background? Why?

It depends on the character and what I do with them. So for Harry I have quite a bit of background, a lot of which has come about from writing prompts and making things up on the fly. But I am generally vague on the dates because of the UNIT dating problem, and also because I keep forgetting just when the new DW episodes and SJA are set. I probably should do myself a timeline, then at least I'd know where I was.

3) What purpose do you feel backstory serves?

Sometimes it's useful because it tells you how they will act in a particular situation. Sometimes it's just nice to know.

4) What have you learned from your character's backstory?

Where do I start? I learnt a lot more about what's there in canon because it was putting that together and trying to make sense of it that helped me come up with some of the stuff in the first place. For example, Will's comment in the Sarah Jane Smith audios about his father's first wife dying and him remarrying and having another family makes it sound as if he and Harry are half-brothers, not step-brothers - and the same surname reinforces that. But I was determined to stick strictly to canon, so I had to come up with a way in which that's true, and ended up with the idea that Harry's mother died and when his father remarried Will was quite young, and so considered his step-father as his father.

5) Is it difficult to play with a character who has little/no backstory? Why or why not?

I don't think it is. Aside from the fact that there's nothing to stop you making it up as you go, as long as you can remember what you've made up and not contradict yourself (and I know that I have contradicted myself). A lot of things you play comes out of what they're like and what you can infer they'll do based on what you do know about them and what they've done in canon.

6) For canon characters: How do you fill in the gaps canon leaves in your character's backstory? How do you explain to those unfamiliar with your canon what a character's backstory is?

I think I already answered the first question above - I take what I already know and get it to make sense and fill in the gaps. For the second question, that's quite common considering that Harry's only in about six stories, so not a lot of people do know who he is. I've never been asked about any of his backstory, but if I did what I'd say would probably depend on the question and how familiar the person asking is with Doctor Who.

8) How much research / work have you put into your character's backstory so far? Are you finished, or is it an ongoing process?

Definitely ongoing. I've put in a lot of thought about bits of it, but not so much about others. Some day I'll get to them, or so I keep saying...