Unreliable or Slow Server
Generally the search engines want to serve their users results that provide them with the best quality user experience. If your site is frequently found to be experiencing outages or down-time, it is subsequently determined to be providing a less than quality experience to it’s users. If the spiders are frequently experiencing difficulty accessing pages within your site, it will be assumed that it is dealing with a site of lower than expected quality.
Duplicate Content
The engines want to provide a wide variety of content to their users in order to best serve their informational needs. If your pages are largely filled with duplicate content from other websites, or content that is thin on information, this is potentially viewed as a negative ranking signal.
Linking To Low-Quality Sites
Linking out from your own site to low-quality pages, or sites deemed to be spam can result in negative quality scores to your own site as well. In general, linking to one or two poor quality sites isn‘t going to damage your reputation too badly, but a large number outbound links to sites of porr quality and spam will almost certainly have a negative effect on your own rankings.
Complexities arise when you have linked to perfectly good sites, which later expire and are picked up by competing webmasters with intent on abusing those domain’s existing inbound links for the purpose of spamming the engines. It’s a good idea to occasionally check where your outbound links are going, you might be hurting your rankings, while supporting a spammer, and not even know it.
Selling Links
The search engines want to provide pure quality content, and view the buying and selling of links as a manipulation of the algorithms they have worked hard to develop in an effort to determine quality. They do not want people in the industry manipulating their algorithm as they view this as a dampening in the quality of their results. If it is determined that you are participating in shady linking schemes or the buying & selling of links for the manipulation of search rankings, you may be hit with penalties to your site’s ranking.
Duplicate Titles & Meta Tags On Multiple Pages
Due to the power signal associated with title and meta tags by many SEO practitioners, failure to create unique meta tags and titles for each individual page can be translated by the search engines as a negative ranking signal. In similar fashion, duplicate meta description and meta keyword tags also have the potential to be viewed as negative factors contributing to your overall rank.
