instand1 - 8:38 am on May 6, 2004 (gmt 0)

One way to detect "paid links" is:
a) do several links to different sites show up together on several sites?
b) does this group of sites show up always with the same anchor-text?
c) does this group of sites link back to a SEO or Internet Marketing agency?
d) does this group of sites have an "unusual" mix of inbound-links from high PR-sites? For example: too many links from high PR-sites?
e) does this group of sites show up in links always at the bottom of the page, as a link-list with no other text between the links?
f) does the words "sponsored links", "SEO", "Internet Marketing" or similar show up on the page?

On webmasterworld there have been several hints that links from the middle of the page, looking "natural", have more weight than links from link-lists at the bottom of the page.