It is very important for SEO professionals to understand how search engines work especially Google, for all major search engines results are decided by machines that use complicated algorithms, there is almost no human intervention in the results, even with Google having a team of quality assurance human editors.
Search engines spam fighting algorithms rely heavily on signals that could be detected and evaluated by machines followed by either taking action against the site in question by itself (very clear spam signals) or to turn a human editors’ attention about that site to do a manual audit, very similar to tax departments where they use signals to audit (along with random audit) a signal could be a person that has been making less than $15 000 for a long time and bought a house that worth $1 000 000 with a 40% down payment. What could be a spam signals for search engines:
- A website that did not change its content in the last few years getting thousands of links in few days from low quality sources
- A new site that has been deserted for years that expanded by 10 000 pages in few days, this expansion was not followed by any inbound links or social media attention.
- 40 outbound links in your blog roll, all of them with a keyword rich anchor text, not very related to your website, furthermore your website is still new with no more than 10 posts or lots of posts with duplicate content.
- 90 % of your links coming with the same anchor text and always dofollow
- 30% or more clicks through rate in your Adsense account
MACHINES like PATTERNS and hate RANDOMIZATION, whatever you do think always if a programmer in Google Plex decided to write a software to track websites doing what you are doing, is that possible? If it’s possible how many websites could be caught using this software, if the answer is millions do not worry about it (i.e. How many websites tweeted twice last week, this is a pattern but millions of sites did that).
Understanding HTML, some programming languages (If this Do that Else .. OR .. AND) will help you for better judgment. Unfortunately some of the red flags above might happen even while you are doing a clean link building but that will not protect you from actions taking by machines (you will pass human review in this case if it happens), those machines are just programmed to take actions based on analysis that they make to your website and link profile, but this will work like removing weeds from a large garden; pulling out weeds manually (human edit) will cause no harm to other plants, however using chemicals (machine filtering) is faster but might kill other good plants. In order to be in the safe zone and avoid any search engine filter RANDMOIZATOIN must be always your friend while doing on page and off page optimization, avoid patterns or any other easy detection techniques.