Defunct domains can be researched through primary sources. Web archives show what was captured and when; state corporate registries confirm whether similarly named companies existed and their status; historical WHOIS and DNS services reveal registration and hosting changes.
Each source has limits, and aggregator sites that blend registry data with people-search listings should be treated as leads rather than evidence. Sound conclusions about a domain's past require at least two independent sources pointing the same way — a standard this record applies to itself.