How to Tell if Link is Good

This is regarding link building. Sorry for dumb question but, with all the odd links being sold other than basic page rank and do follow, how do you tell whether a link is crap or not. I see lots of sites with one page is PR5 and all other pages on site have no PR at all, is this significant. Does it matter whether it was a dropped site or not, another words, if the site is old an dhas multiple pages with good page rank do I care if it was a dropped site and then rergistered. Any insight it would be helpful on how to tell good links from bogus links.

Thanks

 

High PR, low outbound links.

 

You can tell if they are not on googles first page.

 

Links are normally good if its coming form a high PR Page. But make sure link is a dofollow back link.

 

check the pagerank, alexa and the number of incoming links to page, where are u buying your links.

 

A common method is to use the seomoz toolbar to see how strong a link from a page is. It'll give two scores, one for page authority and one for domain authority... the higher these two numbers the more powerful the link.

This is more accurate than PR and alexa etc