After Google’s Penguin update, many common link building practices were made unviable, and even devalued the sites and keywords they once promoted. Many sites that previously had top rankings for their industry keywords found themselves wiped off the Google map because of poor quality links and/or a Penguin “spam flag.” If you noticed a sudden drop in rankings on or around April 24th and/or May 25th, you are probably impacted by Penguin. Google also sent out unnatural link notices around those dates, so if you received one of those, you definitely have a problem. If you received a notice from Google around July 19th, you can probably ignore it because Google admitted to sending out notices on that date by mistake.
This does not necessarily mean you have to rush out and start trying to remove all of your old links. Removing links is a time consuming and frustrating process that you may not always have to do. Certainly prioritizing those efforts to remove the links hurting you the worst is a solid strategy. Deleting links should be a last resort, and not something you should do right away, and definitely not without doing some research first.
There are three reasons to remove links. The first is if you received an unnatural link notice from Google. The second is if you have any de-indexed links as these will hurt the most. The third is if you received a Penguin spam flag, which as noted above, would come in the form of a drastic reduction in keyword rankings on or around 4/24/12 and 5/25/12. Despite which reason you have for removing links, the same approach should be used.
If you received an unnatural link notice from Google, it requires action on your part. You need to show Google that you did your best to investigate and remove any and all “bad links,” and also show good intent moving forward. The unnatural link notice is considered by most to be a penalty put in place by an algorithm that requires manual action to remove, which is why responding to the unnatural link notice is important, or your rankings may never improve.
Start your link un-building process by researching which links are causing the most damage, which are links from sites that have been de-indexed by Google and have an N/A PR rating. De-indexed links should always be removed first. Be sure to only remove links that are not helping your site or rankings (at best useless, at worst hurting your site). Just because you received an unnatural link notice, does not necessarily mean all of your links are bad, so prioritize your efforts to remove the worst links first.
If you need assistance with researching your link profile and prioritizing which links to try and remove first, you may want to enlist the services of a professional SEO firm. The experts at Submit Digital can perform a full site and link profile evaluation to help support you through the process of removing bad links, managing your unnatural link notice, and getting your rankings back by using effective white-hat methods.