Yes, Kurt Vonnegut died. But he didn't write the poem I (and many others) attributed to him. James S. Huggins wrote:
Every six months or so the story arrives in my email. It is a copy of the commencement address that Kurt Vonnegut gave at M. I. T. in June of 1998.
It is a great address. It is very clever. It is inspirational. I encourage you to read it.
And, then, as now . . . it is a hoax.
Kurt didn't write it. Mary Schmich, a Chicago Tribune columnist and Brenda Starr writer, wrote the speech. In her column, published June 1, 1997, Schmich fantasized about giving a commencement address. Then her fantasy address was disassociated from her name and associated with Kurt. It was originally attributed as the address of 1997. It has recently been recast as the address of 1998.
Whoever began circulating the hoax (he's known as "Culprit Zero") started a pyramid across the internet. Like much on the internet it seemed believable, and it carries an implied authenticity — it is "printed". It spread like wildfire.
Hoaxes are an interesting systemic phenomenon. Usually they are used to spread stories of conspiracy theory. They are also a good example of swarm behaviour. The more people believe in a phenomenon, the quicker it spreads and the more difficult to extinguish (see the story of Paul Watzlawick on windscreen scratches in Seattle), and they verify the underlying theory of Appreciative Inquiry ("Change at the speed of Imagination.)
Also read an article of the Washington Post on this issue.