Assuming this spreads, I believe a potential ramification of major sites blacking out would be new laws that would attempt to make such black outs illegal. It

Assuming this spreads, I believe a potential ramification of major sites blacking out would be new laws that would attempt to make such black outs illegal. It could be seen as equivalent to strikes in essential service industries like transportation. Such strikes are semi-regulated and governments can and have ordered strikers back on the job to maintain public order. I see this possibility as a potentially major unintended consequence of putting Facebook "on strike".