There are a couple of really interesting animated documentary blogs around, which give an interesting over-view / perspective on the genre.
Dr Bella Honess Roe teaches at the University of Surrey and is one of the preeminent scholars in the area. She did her PhD about animated docs and is in the process of turning her research into a book on the subject (which is great, as a key text is really needed). Her blog, Animating Documentary (it doesn't all have to be fly-on-the-wall...), is a series of thoughtful reflections on issues around the subject.
Alys Scott-Hawkins and Ellie Land come at animated docs from the perspective of film makers. Alys has made several fascinating and provocative films including The Road to Recovery, a commission by Rethink & Young Minds which uses drawn animation to articulate the experiences of young people with mental illness. Ellie is making a film called Centrefold for The Wellcome Trust about labiaplasty which is really thought provoking and a fascinating companion piece to her film Everything was Life, about female genital mutilation.
Alys and Ellie have set up a blog called Animated Documentary (there is also a Facebook community here) which is turning into a really helpful compilation of work / meeting place for film makers / discussion point.