How can we differentiate spam links to good link building services?

How can we differentiate spam links to good link building services?

How can we differentiate spam links to good link building services?

I recently order link building gigs worth more than $15.

He delivered as promised. But when i check the links, the links are from high PR blogs but I feel like that my link was spammed.

is that good? how can i know it is really spammed?