Fake consumer reviews have different forms.
Positive fake reviews aim to promote products or services and are written or paid by brands or sellers. Thus, some book authors have been caught red-handed on Amazon.
Obviously, negative fake reviews are created by competitors.
Fake reviews are common on travel and hotel websites because on these websites consumer reviews are an important choice criteria.
Dedicated agencies (often offshore agencies) offer fake review services. At the same time, ecommerce websites develop filters and algorithms to block fake reviews. Cornell University has developed a filtering review algorithm.
In most countries, fake reviews are illegal. In the US it breaks the Federal Trade Commission’s truth-in-advertising laws.
Fake reviews characteristics according to Cornell research: