"Similarly, Joseph Gentle who is an ex Google Wave engineer and an author of the Share.JS library wrote: Unfortunately, implementing OT sucks. There's a million algorithms with different tradeoffs, mostly trapped in academic papers. The algorithms are really hard and time consuming to implement correctly. ... Wave took 2 years to write and if we rewrote it today, it would take almost as long to write a second time."
[1] http://en.wikipedia.org/wiki/Operational_transformation