Post Penguin-Panda updates from Google, there has been several instances where over optimization of backlinks, or following very thin and aggressive patterns in links have invited penalties on Google SERPs.
One start up website I had worked on earlier lost its ranks due to two reasons, during the Panda update back in mid 2012. One, there were several (in fact, excessive) instances where the backlink anchor text was exactly the same as the targeted keyword. Two, there were several low quality link sourced from made-for-link-building blogs.
The site dropped out of Google SERPs completely for one keyword that was occuring more than 80% in the anchor texts. For other keywords, which was still being repeated, but in limited numbers (10-20%) was not penalized.
Finally, we had to remove all those links, before submitting a re-inclusion request with Google.
A recent experiment done by Court Tuttle of Blog Builders, has re-inforced some of the above findings along with some amazing new findings.
Findings from the experiment.
- It is possible to positively influence rankings using significantly few exact match anchored links if they are from highly relevant pages on relevant sites.
- It remains possible to rank for fairly difficult phrases quickly with a brand new domain.
It is a significant finding, especially in a post-penguin/panda world where excessive back links and over-optimization can win you penalties more than accolades.