How does a Prioritizer of a Webcrawler Frontier work?

Hi i am pretty Knew on stackoverflow and know that i am certainly doing something wrong but please bear with me.

Now for my question. How does a Prioritizer of any Webcrawler FRONTIER work? I am writing a seminar Work on Webcrawlers and found out about the Frontier in itself but the interesting parts like the "Prioritizer" which is a pretty important component in my opinion, are still amystery to me!

Is there some Paper or any information about the specific implementation on how the prioritizer Knows which Site has a higher Priority?

I imagine it has something to do with the Pagerank but is that all?

THX for any help