.io is especially popular because it resembles the computer term “input-output.” It is huge with start-ups and IT companies.

Well, those companies should also have the technical chops to know better.

I still think that most of opening up the TLD space was a mistake, not just the two-character stuff. Very few new TLDs have actually provided a lot of use, but they have created a “brand tax” on companies that don’t want confusing use of similar registrations and who then go register the equivalent domains.

.biz vs .com is a great example.