The idea of collaborative annotation has been around since the beginning of the web. I tried to launch an annotation startup myself back in 2000, and there were several funded competitors back then. It never catches on. It would be interesting to analyze why people just don't use these systems when given the opportunity. Is this a solution in search of a problem?
I think the dynamic is similar: while a normal annotation is a comment on a fragment of text, a Twitter reply is (or at least can be) a comment on a single portion of a longer thread.
Two notable differences:
- While a typical annotation platform takes a freely-written text and allows any segment to be annotated, Twitter forces the author of a thread to compose their text with the segment boundaries in mind.
- While a normal annotation system doesn’t allow you to annotate the annotations, any given “annotation” on Twitter may itself be a thread which allows for annotation. It’s recursive!
Maybe the above is a stretch, but personally I think it’s an interesting way to think about Twitter.