You may create and operate only one (1) account. Owning more than one account is basically the only way to "cheat" on NeonMob. Real artists earn a living through sales on NeonMob, so obtaining free packs beyond the standard daily allotment is stealing. Collectors who participate in NeonMob fairly become enraged when they see people using multiple accounts to funnel pieces into one account. So don't do it. Don't make your best friends sign up only to make them trade you all their best pieces either.
Violating this rule can be grounds for suspension or deletion of your account, including the seizure of your entire collection.