Buying pops traffic

I can see a lot of pops url are starting with the below domains:

dt2xr6g2i5.com
i62e2b4mfy.com
engine.spotscenered.info
jf71qh5v14.com
dt2xr6g2i5.com
go.oclasrv.com
vinfdv6b4j.com
i62e2b4mfy.com

How can I identify what are the actual traffic platforms, so I can buy traffic from them?