When is a character/word *learned*

Just curious:
When does Skritter mark a word or character as learned for stats purposes?
What does it take for an item to be ‘unlearned’?

Good question! A character is marked as “learned” when it’s graded as correct at least 24 hours after first seeing it, and a character is counted as unlearned whenever it’s graded as wrong (1). Here’s a link to more details on the SRS: http://docs.skritter.com/article/51-spaced-repetition