Millions of businesses have spent billions of dollars branding with .com over the last 20 years. Consumers have been conditioned to trust sites that reside on .com (or appropriate ccTLD). Using anything else for a business causes doubt and shows consumers that you should not be taken seriously.
Over the years, there have been plenty of new TLDs launched with hype to be the next .com contender, but those promises never materialized. Just look at .travel [18k domains] (huge industry with billions in revenue), .biz [2.6m domains] and .pro [111k domains] (for those serious about doing business), .mobi [965k domains] and .tel [138k domains] (mobile is the wave of the future) and .asia [280k domains] (biggest population in the world). The sum of all new TLDs released post-2000 still isn't a threat to .com's dominant position with 113 million domains.
|