The ratio I check before anything else is what share of the site's own outbound links are paid placements with commercial anchors. This thread is all inbound signals, traffic, relevance, ranking keywords, and those are worth checking, but they tell you what a placement is worth today rather than whether it survives. Google has been deindexing domains that exist mainly to sell links, and the footprint on the ones that vanish is consistent: most outbound links paid, money anchors, commercial targets. A host with genuine visitors still zeroes your link the day it drops out of the index, and neither DR nor a traffic graph gives you any warning that it is coming. Practical version is scrolling their last twenty posts and counting how many are sponsored with an exact match anchor out to a commercial page. If most of them are, the metrics do not matter.