Retroactively require anyone with less than "x" post count, or less than "x" account age to do at least a bit non-trivial promotion of NEM. The ones who do it validate their accounts as non sock puppets and the rest get wiped from the investors list. Seems like the best trade off. Someone can still get multiple accounts, but at least make them work for it.
The most effective promotion is done communicating directly to others one thinks might be interested in NEM, and would generally not be verifiable. By asking people to promote it in places you can verify it, you're encouraging people to spam random websites with ads, which would hurt the cause more than help it. And it wouldn't take people more effort than creating multiple btct accounts to create a bunch of accounts for other sites to spam them.
This. Crypto gets enough spam. This getting lame and annoying.
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