Backlinks (incoming links to your website) are a primary part of most search engine algorithms - obviously you have some really good content if a lot of people want to link back to it! But Google and the other search engines care about quality links more than the quantity of links and if "toxic" sites are linking to you, your rankings may suffer. A toxic backlink can be from irrelevant paid links, link farms, spammy sites, etc. We recommend at least an annual check of your backlinks with a strategy in place for backlink removal.
Here's a quick step-by-step guide to backlink removal from your Simpleview SEO team:
Step 1: Pull your backlink report via Google Webmaster Tools and start evaluating the sites linking to you. You might want to brew a pot or two of coffee - this is not a small undertaking. Any link that you're not proud to have back to your site you may consider having removed. You may also use other helpful tools like Open Site Explorer for this monumental task.
Step 2: Decide which backlinks will not be useful to your site and find contact information for those sites' webmasters. You'll want to draft an e-mail, send it, and follow up 2-3 times in the next month or so, so make sure to keep track of who you've contacted and when.
Step 3: Via Google Webmaster Tools, follow the steps to disavow links. By doing this, you'll be asking Google not to take certain links into account when assessing your site.
Cleaning up your backlinks is time well spent, but remember that backlink correction is just one of many steps to making sure your site ranks well. Make sure backlink correction is just a piece in your annual SEO strategy.
Contact your SEM analyst if you have any questions about the above process or would like to know more about how or why it's done.