Metrics to determine the quality of a link?

[nicole.healthline]

I found this very useful post on SEOMoz http://www.seomoz.org/blog/525600-metrics-how-do-you-measure-measure-a-link, but its a bit dated.

Also, it doesn't really help in terms of applying exact metrics to measure the quality of a link. Does anyone have any other suggestions to help automate / determine the quality of a link?

[brycebertola]

Obviously you can look at PageRank, Domain Authority, and a slew of other factors, but I don't think there will ever be an exact metric to determine the value of a link.