Kune

The idea already exists in many code editors, but for blocks of code. I would find very helpful a pair of buttons "Expand all replies" and "Collapse all replies", especially as a wave becomes more complicated (as is usually the case with successful waves). A wave with expanded replies is easier to make a browser-conducted full-text-search in, while a wave with collapsed replies is easier to read and get the "big picture". It is also easy to implement, as the functionality per single reply already exists. First-level blips don't necessarily need to collapse, although that could be useful to bring distant blips in the same view for cross-reading.