To biblical times for all instruments but not for the dollar - there were no dollars in 'em days but sons of bitches, yeah.
Because it's all Java, it's platform (operating system) independent. While there are some other Java charting packages out there, most of them are pretty basic, without script language and backtesting capabilites. However, the biggest drawback for me is that it can be only started from within the browser, like the browser based TWS. This means forced upgrades - one thing I can't stand. If they ever decide to offer a stand-alone version of the Prorealtime package, then, yes, maybe...