I'm not completely sure what you need here, but the sentence can be rephrased thus: the ultimate power to decide (two things): 1) who has an opportunity to be heard and 2) what we are permitted to say lies ... with ... In other words, these companies will be able to decide which people will have access to the internet and which messages those people will be permitted to send through the internet.
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CalifJimwhat we are permitted to sayThanks, CJ.