I didn't notice in those write ups but the Senator doesn't even have to talk On Topic. Just stand up and speak. I seem to remember my PolySci professor saying that the Bible has been read into the congressional record by filibusterers more times than any thing else.

What makes it effective, is that all progress is stalled, eventually the leadership has to cave, so congress may deal with more pressing buisness. edit (presuming the 60 votes necessary to end debate cannot be had.)