Citation Flow is a trademark quantity metric developed by software company Majestic.com to predict the quality of a website based on its popularity – or the number of links pointing to it. Every link pointing to a site has a Citation Flow value between 0-100 with a higher number indicating a higher quality value. Citation Flow also determines the link equity or influence, your site has and may pass on.
You may think that having a high Citation Flow score would be positive, however, having a large number of links means nothing if the majority of the links pointing to your site turn out to be robot sites, spammers, random and little-known blogs with spammy content and low metrics. Having a high Citation Flow from numerous low-quality sources does little to indicate your site is an authority and should be ranked, and your site is likely to have low Trust Flow.
Citation Flow is used alongside their other flow metric, Trust Flow, which primarily focuses on determining the trustworthiness of a site by seeing how closely it is linked to a site known to be trustworthy. Ultimately the ratio of Trust Flow and Citation Flow are used to assess the overall authority of a website based on its backlink profile. The closer the ratio between the two metrics, the better as this indicates that the majority of the backlinks are of good quality.
Ideally, you want every link you acquire to be a trustworthy link, represented by a citation-to-trust ratio of 1:1. However, the average CF-to-TF ratio is closer to 2:1, or 50%. Anything below this means that the majority of your links are low quality.
For example, if your Citation Flow is 30 and Trust Flow is 15, then you have a ratio of 2:1 which is average. However, if your Citation Flow is 100 and Trust flow is 15 you have a ratio of 20:3, indicating that although you may have a good number of links, the majority of them are of low quality and action should be taken to address this issue.
Majestic is a third-party tool and its metrics are not used by Google as a ranking factor, however, Flow Metrics can be a useful indicator of quantity which can aid search marketers when making strategic decisions.