not actually replaced flash-based editing, but adding another option.
You can edit openstreetmap in a number of editors, with a number of different technologies:
Some of them are:
iD : HTML5-based, in-browser editing
Potlatch : Flash-based, in-browser editing via flash player plugin
JOSM : Java-based application, run from local machine, or via JNLP
Vespucci : Android application, works nicely with touchscreens
Meerkartor : QT application
Openstreetmap is open, and as such there's loads of different ways of using it (or updating it).
I've been contributing to openstreetmap since the days of the java applet editor (which used the processing libraries), before the data structures had been fleshed out. It's come a long way from a few scrawls representing the paths around Regents Park in London.