Remus Lupin, anyone?
Scholastic recently conducted an interview with JK Rowling in which she admits to having written the full biography of Remus Lupin. She isn't specific, but I would bet it is for Pottermore...perhaps when POA is loaded onto the website? Just a guess...
The interview is lovely. If you have the time to listen to it (while doing other things, like me) go and do so.
Harry Potter Reading Club
And for those of you who were sorted into Hufflepuff, she says some lovely things about Hufflepuff, too. :-)