Mr. Hall's original and current thesis is that adding TLDs as
an act is harmless, and that the real point of concern is the number
of queries.
This point has not yet been disproven. The counter-argument
that a busy ("popular") TLD will result in more queries only proves
the point,
although the advocates of such an argument refuse to admit that the
frequency of queries -- the number of queries over time, the
measure of "popularity" -- is the issue, not the number of TLDs.
Except that the cache misses hitting the root are by no means *linearly*
proportional to the number of queries. As the popularity of the servers
in a domain increase, the load on the root grows asymptotically towards
1 request per TTL per resolver, and in fact it approaches the limit
quite fast. Split .COM in two, both halves will be very the asymptote,
both would generate almost the same load on the root as the previous
combination. Adding more TLD and splitting the existing load across
these new TLD would definitely have an impact on the root.
-- Christian Huitema