This is an interesting detail from Ryan Sleevi > So I don't think this buys any improvement over the status quo, and actually makes it considerably more comple

This is an interesting detail from Ryan Sleevi > So I don't think this buys any improvement over the status quo, and actually makes it considerably more complex and failure prone, due to the cross-sectional lookups, versus the fact that .invalid is a reserved TLD. So it should be more likely for shared hosting services to recognize that .invalid is an explicitly reserved TLD, vs correctly walking subdomains and recognizing "effective TLDs" (which vary in number of dot-separated elements).