I have been thinking about this as well lately, and it was interesting to see it actually posted online this morning: Is Slashdot the driver of Buzz that it once was? [here]
I would be tempted to say that the impact of the Technorati, and uber-linking and trackback phenomena are more important to Buzz now then Slashdot. Slashdot was the go-to place for hip and cool news about the world of geeks. Now, blogs and the associated tools do the same job.
Will Slashdot fade away? Not likely. The more important question is whether it will evolve. What could Slashdot do to make it more relevant to the blog-focused techophiles?