Hoople - 2:39 am on Jun 30, 2010 (gmt 0)
I've found the links from this site to be valuable only to very very small sites, ie a niche site in a niche within a niche. Said differently a sector full of mostly hobby sites with <10 authority sites. In WW speak: 'red widgets collected by little old ladies in the USA'.
Only in that case for results I've seen it be helpful to Y!, less for Bing and slightly to nill for Google.
On my other sites with many PR3 and above inbound links: a link from aboutus.com was a part of the 'link noise' (past 200 in the backlink listing).