To me slashdot was critical in galvanizing the geek community and bringing free software to the mainstream in the late 90's. The comments added incredible value and created a community that I had not come across anywhere else.
I think the high point of that period was the announcement of the open-sourcing of the Netscape code base. Nowadays, itt is hard to imagine the need for all the stories on how to convince your boss to use this software some dude in Finland wrote.
Slashdot also championed everything2.com, kind of a proto-wiki.
The low point was all the trolling in the article about death of W. Richard Stevens, which lead to much of the moderation code that needed to be put in place.
Rob's run at slashdot was pioneering and hugely influential. I look forward to his next project.