Well take this for example: http://genius.com/5079163/github.com/rails/rails/blob/master/activemodel/lib/active_model.rb http://genius.com/5079163/github.com/ra

Well take this for example: http://genius.com/5079163/github.com/rails/rails/blob/master/activemodel/lib/active_model.rb http://genius.com/5079163/github.com/rails/rails/blob/master... This annotation will always be on the version of active_model.rb at master, even if it changes. And we try pretty hard to anchor annotations even when the underlying text changes. Here's a talk I did explaining our approach to "fuzzy annotation anchoring" if you're super interested: https://www.youtube.com/watch?v=FJyqfRcyYIQ https://www.youtube.com/watch?v=FJyqfRcyYIQ But it's definitely not perfect! Hit me up with suggestions: tom@genius.com