The larger problem is that all the extensions beyond nation-state country domains and one
international domain (which by default is currently ".com") are unnecessary, and largely unworkable in terms of ensuring niche content adherence.
If you want information on, say, treatment for kleptomania, you go to a search engine and type in "kleptomania." That's want seach engines do.
So if there was, say, a kleptomania center in Mountainview California (also, oddly enough, the worldwide headquarters of Verisign) that wanted to establish itself as one of the global leaders in kleptomania research and treatment and they needed a good, memorable domain name, they could try to buy "kleptomania.com." But failing that, they could also get "kleptomaniacenter.com," "mountainviewkleptomania.com," "kleptomaniatreatment.com," "kleptomaniainstitute.com," etc. There are a lot
of workable domain names for this fine institution to choose from. As for getting found by internet searchers, that's what search engines and other media are for. And if they really want to be number one in the world, well, then, they'll just have to dig deep and buy the prime domain for their industry, "kleptomania.com." But they can still be tops without it. Microsoft doesn't own "software.com," and they've managed to make some decent headway into that market. (Full Disclosure: the Mountainview Kleptomania Center doesn't exist...I made it up as an example. Hope everyone's okay with that.)
As for the perennial cry from new extension enthusiasts that we're "running out of names" in .com...please. 67-character domain names offer many, many times more unique domain name possibilites then there are underlying numeric IP addresses, which currently offer over four billion possible addresses. There is no shortage of domain names, and I would say no shortage of even "workable" domain names...and most registered-for-resale domain names outside of the top and second-tier are available for a few thousand, or even a few hundred dollars. Plenty of domains for all.
The other problem of "specialty" extensions is, who's going to pay for compliance? Ensuring that hundreds of thousands of specialty domains are being used only for that "specialty" purpose is very expensive: you have to monitor, make decisions on infractions, communicate and arbitrate, and be prepared for litigation. Will the business model provide enough revenue for that? Who will ensure that every .info domain is being used to offer real, genuine, bona fide "info?" Who will protect the ".info" brand? Where will they find the money to do it?
And why bother?
Take ".aero" for example...what possible use is a specialty name to airlines? If people need an airline, they find it through a type-in guess at the company name URL, a search engine, or from media. If they get to a website that's not the one they're looking for, they leave pretty quick.
No one in aviation needs ".aero." and the same goes for every other new extension, including .biz and .info.
So why all these new extensions, and talks of even more? It's all because of the domain registration industry. Domain registration is world's first genuine license to print money. Other than the basic IT and admin and marketing structure you find in any business, the "product" of the domain industry--domain names--requires nothing to produce. There's no manufacturing, no research, no development. Get license (from ICANN) and print...this was all about the money.
I think the speciality extension part of the domain industry will ultimately collapse under the weight of its own uselessness. The registrars and speculators in this particular market will continue to howl about the wonders and necessity of all these new extensions, and the big corporations will continue to register their own brand names as a necessary form of TM protection (TM law requires continuous vigilance of TM rights in order to maintain TM rights), but this will result in very little long-term business.
Nic made a good point as well about the non-development of specialty domains because of speculators holding them will significantly limit their visibility to internet users. Sometimes, greed cancels itself out.
Speciality Extensions: they're not technically necessary, they can't be properly administered to ensure appropriate content compliance, and they don't have any marketing momentum.
I think ten years from now, if we still have the DNS, the specialty extensions will be rememberd as one of the nutsy little jokes of the internet.