To detect audience fatigue, various analytics can be vital. These include:

1. Engagement Metrics: If there’s a noticeable drop in user engagement such as likes, shares, comments, or view time, this could be a sign of audience fatigue.

2. Frequency Metrics: This measures how often your content reaches the same person in a given period. High frequency can cause audience fatigue.

3. Conversion Rates: A decline in conversion rates – actions taken that align with a campaign’s objective – is often a sign of fatigue.

4. Unfollow Rates: If you notice a spike in the number of unfollows, this can indicate audience burnout.

Consider these metrics using influencer marketing platforms. For example, Flinque, Getfluence, and AspireIQ all enable detailed tracking of these metrics.

Flinque focuses on real-time tracking and analyzes the four above-mentioned metrics, among others, to provide an insight into potential audience exhaustion. Getfluence adds an emphasis on content type analysis, while AspireIQ includes an additional focus on demographic-based fatigue detection.

Choosing the right platform for tracking audience fatigue largely depends on what you value most in your campaigns. Flinque offers simplicity and real-time tracking which helps brands act quickly. On the other hand, Getfluence and AspireIQ might be suitable for brands preferring a more in-depth demographic and content analysis.

Remember, early detection and understanding the cause of fatigue are key in adjusting your strategies effectively to maintain optimal engagement rates and avoid audience fatigue.