SEO activities of every company involves building backlinks and more the better. Since the Panda update the focus to create backlinks has shifted to quality and people look at various metrics of a backlink before creating them. There has been a evolution on this front and multiple ways of creating backlinks as well as link building services are available at a right price. A website owner or agency keeps working on its objectives until the desired results of reaching the first page of Google are achieved. During this exercise tons of backlinks are created running into thousands.
And Bang here comes a Google Algorithm Update which says that one of the practises is foul in Link Building and your site drops in rankings. You get a penalty and you are looking at lost traffic for a pretty long time. Google says the road ahead is simple, remove unnatural links to your site by either disavowing them using the Google Disavow Tool or get them removed.
Let?‚EUR(TM)s get down to the question which is going to be asked a lot of times down the road, What are Bad Backlinks?, Google does not provide a clear definition of what bad backlinks are, but my guess is as follows:
1. Backlinks from Irrelevant Sites
2. Backlinks from Low Page Authority Sites

Analyzing Bad Backlinks
There are a few ways from where a SEO Professional can start weeding out the negative backlinks from a site affected by manual penalty or rankings in Google. First step in the process of finding bad backlinks is having all the backlinks in one excel sheet. You can find out backlinks to your website through multiple sources. Since Google Webmaster Tools does not show all the backlinks to a site. Though the first step will to be consolidate all the available backlinks to your site. Follow the steps mentioned below to gather all the backlinks in one excel sheet.
Step 1: Go to Google Webmaster Tools and under the Links to your Site option under Search Traffic, click on Links to your site. Click on Download this table to download all the domains linking to the site as shown below.

Step 2: In this step we look at other tools to identify the backlinks to the site. One such web tool is 99webtools.com which uses Moz API to identify the backlinks to a site.
Step 3: Another free backlink checker tool available out there is it gives you access to over 1000 backlinks to your site.
Once you have the list of all the backlinks to the affected site from the above steps, put them in one excel sheet/notepad. Quality of the link can be checked with Page Authority and Domain Authority parameters assigned While Domain Authority here is a better parameter to judge it when compared to Page Authority as Domain Authority is authority of the basic domain.
Domain Authority Check for Backlinks:
To find out all the Domain Authority of all the backlinks in one place, I suggest the free tool netpeak checker which you can download

After Installation, untick the Index Domain and Index Url from the left side as highlighted below to avoid captcha from Google and temporary search band of your IP for hitting Google with too many search queries. This is likely to happen if you enter even 100 backlinks. If Index options are ticked this tool will send one query for every URL to Google to find out the number of pages indexed in Google. This information is not useful to us for finding bad backlinks.
Next Copy all the URL?‚EUR(TM)s and click Load in Netpeak software. Paste the URL?‚EUR(TM)s into the box as shown below.
Click on Save and Click Start Check.
Once the check is complete, Export the results by clicking Export at the top left of the page as shown below.

Once we have the Domain Authority of the sites, we can then choose to set a benchmark of quality to find out bad backlinks. My parameter is DA of less than 20, any site which has Domain Authroity of less than 20 is not going to contribute much positive power to any site, thus I suggest to disavow such link using Google Disavow Tool. Using the filters in Excel shortlist the sites with DA