Question: was there a similar point in history that was so effective in giving power to the common individual as what computers have done the last 20-30 years?
Probably it started with the printing press and movable type. Later, the mimeograph and photocopier. But 'mimeo' and 'xerox' both were well before the last thirty years - although samizdat
and it's close cousin the 'zine' are still useful and used today. Especially in places where the web is heavily censored or monitored. Samizdat was a material factor in bringing down the Soviet Union - and later preventing the success of a coup that attempted to bring it back.
Prior to the web I think BBSs and Fidonet in particular could be considered equally empowering. Many of Fido founder Tom Jenning's less radical views fit in very well with current F/OSS principles.
But it was still very male and "geek" for the most part.
In general, anything that enables broad and unrestricted free communication is a force for social change. Whether it is change leading to liberation or oppression depends on who is behind it.
Where the PC/Web combination truly succeeded was in bringing global access down to the level of virtually anyone
. I believe that really was
a pivotal and totally unique achievement in human history.