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HF 20 will likely make the account creation price completely free. This means that anyone can create an account creation service, from Steemit.com to Busy.org to Utopian.io or anyone else.

These account creation services will likely be free and instant as well. HF 20 will also change bandwidth limits and make it so that new accounts do not come with free SP (but can still vote and everything).

This way there's no incentive for spammers to spam up new accounts anyways, and the account creation services themselves can come up with ways to deter spam.