Furthermore check this out. "In order to get rid of the spam quickly, we removed from our list of 25,000 sites all that were not listed in any of the major web directories". More evidence of their heavily reliance on leeching intellectual property value from the major directories.
As for seeds, in this paper the seeds they refer to are only potential page candidates that are likely not to be spam (based on silly assumptions such as above) to kickstart an algorithm for spam detection based on propagation of "non-spaminess" measures. The paper does not discuss PageRank algorithm seeding.
Great papers though for finding out how they are thinking. Thanks.
[edited by: Bottler at 11:17 am (utc) on April 1, 2004]