Taboola/outbrain and similar platform, need infos.

Hello can someone give me an idea of the cpc and ctr of sites like taboola or oubrain? (Mention if is tier 1 traffic)

I heard also about Content.ad, what do you think about it? It's easier to get accepted?

I heard that the other two needs something like 500k views/day it's true?

Thanks!