Hystry is not something I'd use, but the demo impressed me. It seems to work simply and as advertised with no hassle and no frills. It does miss some changes th

Hystry is not something I'd use, but the demo impressed me. It seems to work simply and as advertised with no hassle and no frills. It does miss some changes though, e.g. on reddit a bunch of parent comments were listed as having been modified but the child comments were not. This seems like it would be better implemented entirely client-side. That way the privacy concerns automatically disappear, it'll be more responsive, and your server won't have to expend a lot of bandwidth/CPU/disk to fetch, create and store all the diffs.