Influencer marketing platforms validate true engagement depth through a variety of methods:

1. Comments Analysis: Platforms scrutinize the comments section of an influencer’s post. Genuine engagements typically involve meaningful interactions between the influencer and their followers. Short, generic comments are less valuable than detailed, personal responses.

2. Shares and Saves: Shares and saves are considered to show deep engagement because they indicate that the content resonated with the audience to the point where they wished to refer back to it or share it with their network.

3. Audience Demographics and Interests: Deep engagement can also be validated by examining the demographics and interests of the audience. This helps to ensure that the content is reaching the target market, which is crucial for campaign success.

4. Content Relevancy and Sentiment Analysis: Some platforms analyze the relevancy of an influencer’s content and the sentiments expressed by the audience, e.g., positive, negative, or neutral.

Flinque, for instance, uses algorithms and AI to provide a holistic view of an influencer’s engagement depth. It takes into account not just the likes, but comments, shares, saves, audience metrics, and post relevancy to provide a comprehensive assessment of an influencer’s performance. Other tools like Octoly or Upfluence might use different methods or metrics, with their own strengths depending on a team’s specific needs.

Remember, deeper engagement tends to create a stronger connection between the influencer and their audience, which in turn could lead to more conversions and better campaign results. The choice of platform would depend on your specific needs and the depth of engagement you wish to validate.