Restricted usernames differ from blocked usernames in one key way: they are available, but with conditions. A brand name like nike might require proof of trademark ownership. A celebrity name like elonmusk might need identity verification. A geographic term like newyork might be reserved for official city accounts.
The implementation involves queuing instead of rejecting. When a user tries to register a restricted username, they enter a verification flow instead of seeing an error. This could be document upload, email verification from a corporate domain, or manual review by your trust and safety team.
Common restricted categories include brand names (Fortune 500 companies, major tech brands), celebrity names (verified public figures, politicians, athletes), geographic terms (major cities, countries, states), and organization names (universities, nonprofits, government agencies). Each category might have different verification requirements.
The business logic depends on your platform. A business networking site might require LinkedIn profile verification for company names. A gaming platform might allow celebrity names but add a "not affiliated" disclaimer. A social network might auction restricted handles to the highest bidder. The restriction system provides flexibility that simple blocking cannot.