Influencer marketing platforms typically measure audience saturation by analyzing the overlap between audiences of different influencers engaged in a campaign. This is done by using audience analytics that track the percentage of followers that multiple influencers have in common.

For instance, platforms like Flinque allow you to analyze the Influencer-overlap ratio of your campaign. If it’s high, it means there’s a lot of overlap, showing that your audiences could be seeing your campaign multiple times, possibly leading to audience saturation.

In addition, engagement rate over time can also be an indicator. If the engagement rate drops substantially during a particular campaign, it might suggest that the audience is becoming saturated, given that other factors are stable.

On the other end, platforms like Traackr provide audience retention data. A steep fall in audience segments could indicate over-exposure or saturation.

Furthermore, social media platforms also provide insights into reach and impressions for posts. A substantial mismatch between reach and impressions could potentially hint towards audience saturation. For instance, if your reach is high, but impressions are not parallelly increasing, it may point towards saturation.

However, analysing saturation is more than just a numbers game. Understanding audience behaviour, their content preference, consumption habits, and individual influencers’ posting routine are important. Flinque, for instance, integrates behavioural information into its analytics.

Importantly, the methods and metrics mentioned above can give you a rough indication of audience saturation. However, the measures will differ based on your specific goals, campaign nature, and audience type. Before deciding on the metrics, it’s important to have a clear understanding of your campaign objectives and audience. Understanding saturation and using it correctly can guide you to refine your influencer strategy, creating a balance between reach and resonance.

Remember, while saturation is important and too much can reduce campaign effectiveness, each brand will have its own saturation threshold depending on various factors. That is why such platforms offer custom solutions.