The truth is, bad links produce bad results, so you don't want links from farms, irrelevant websites, pages with low PA scores, untrusted websites, irrelevant forums, low - quality directories, widgets, or with over-optimized
spammy anchor text.
Not exact matches
On top of that, the backlink checker also identifies if any links were taken away, if the links were NoFollowed, if the
anchor text changed, or if the page that holds your link all of a sudden becomes populated with
spammy content.
Either they have a very low number of links (not enough power) or they have too many bad links (
spammy links from untrusted and / or irrelevant sites), or they have an
anchor text over-optimization penalty (Penguin), or a link velocity issue.