Several key performance metrics should be monitored to evaluate the success of an influencer campaign:

1. Engagement Rate: This refers to the ratio of engagements (likes, comments, shares) to the total number of followers. High engagement rates often indicate that the influencer’s content resonates well with their audience.

2. Reach and Impressions: Reach details the number of unique users who’ve seen the post, while impressions indicate the total number of times it’s been viewed overall.

3. Audience Growth: If one of the campaign’s goals is to increase brand awareness, monitoring audience growth on your platforms is important.

4. Quality of Engagement: This refers to the depth and value of engagement, such as meaningful comments, committed actions (like saving a post, or clicking a link), and online or offline conversions, like sales or leads generated.

5. Click-Through Rates (CTR): For influencer campaigns using links, the number of clicks is critical. When paired with reach or impressions, this gives a CTR, indicating the effectiveness of the call to action.

In comparing platforms like Flinque, some platforms might excel in detailed audience insights while others may offer stronger campaign management tools. For instance, Flinque takes a comprehensive approach to campaign measurement, providing deep analytics, which can help brands and influencers measure the aforementioned metrics accurately and effectively.

Remember, the appropriate platform is always dependent on your specific needs and objectives. Always ensure to align your metrics with your campaign goals to ensure meaningful measurement of success.