QUOTE: “common with forums is low-quality user-generated content. If you have ways of recognizing this kind of content, and blocking it from indexing, it can make it much easier for algorithms to review the overall quality of your website. The same methods can be used to block forum spam from being indexed for your forum. Depending on the forum, there might be different ways of recognizing that automatically, but it’s generally worth finding automated ways to help you keep things clean & high-quality, especially when a site consists of mostly user-generated content.” John Mueller, Google
If you have a commenting system (like Drupal, Joomla or WordPress) that allows for search engine friendly links (commonly called dofollow links) from your blog or site, you will probably, eventually be the target of lots of spam, be complicated in tiered link schemes and potentially fall foul of Google’s webmaster guidelines on using the attribute in certain situations.
QUOTE: “Expertise, Authoritativeness, Trustworthiness: This is an important quality characteristic. …. Remember that the first step of PQ rating is to understand the true purpose of the page. Websites or pages without some sort of beneficial purpose, including pages that are created with no attempt to help users, or pages that potentially spread hate, cause harm, or misinform or deceive users, should receive the Lowest rating. For all other pages that have a beneficial purpose, the amount of expertise, authoritativeness, and trustworthiness (E-A-T) is very important..” Google Search Quality Evaluator Guidelines 2019
According to the U.S. Commerce Department, consumers spent $453.46 billion on the web for retail purchases in 2017, a 16.0% increase compared with $390.99 billion in 2016. That’s the highest growth rate since 2011, when online sales grew 17.5% over 2010. Forrester predicts that online sales will account for 17% of all US retail sales by 2022. And digital advertising is also growing strongly; According to Strategy Analytics, in 2017 digital advertising was up 12%, accounting for approximately 38% of overall spending on advertising, or $207.44 billion.
One common scam is the creation of "shadow" domains that funnel users to a site by using deceptive redirects. These shadow domains often will be owned by the SEO who claims to be working on a client's behalf. However, if the relationship sours, the SEO may point the domain to a different site, or even to a competitor's domain. If that happens, the client has paid to develop a competing site owned entirely by the SEO.