One of the main reasons I used short URLs before was twitter, but they shorten* all of them for you now.
*Unless the original URL is less than 22 characters, in which case they conveniently _lengthen_ it for you. Which includes many of the unshortened links I post. I even recently set up my blog so posts have a ~9 character permalink. So twitter would award me with about a dozen bonus characters.
I especially hate that behavior as occasionally I'm talking about a domain name (maybe one that is having a DNS issue), not a URL, and Teitter insists on making it a lengthened URL. I've seriously taken to putting zero-width space characters before the .com to break its detection.
What do people use short URLs for nowadays? I used to run one that was "dynamnic" in the sense that you had a number of services that it could resolve and specific data you would send the services. But it never gained traction.
/g/search+query
/bing/search+query
/amazon/product+search
/g.images/image+search
etc.
I mean, you mentioned Google, so yes, expect 200-300+ character links for the most simple of urls, with about fourteen layers of different metrics baked in.
Nothing worse than trying to get a link from Google search results.
I guess that's what I'm asking. The only thing I know it's really useful for is making small QR codes. Of course, a lot of people would disagree about the utility: http://picturesofpeoplescanningqrcodes.tumblr.com/
The same reason Google owns Gtaxes. It might be useful in the future and better to have it yourself than someone else? I'd imagine FB would want to squat on it at least.
Nothing special about a tld resolving. You can put an A record on anything. Many companies set up internal DNS names like "go" or "wiki" so that they resolve to helpful internal tools. This is like a public version of that.
Theoretically, I suspect, this should be possible, as an empty-named A/AAAA records on root DNS servers, although dig(1) and host(1) failed to produce such query for me.
The browser is automatically putting "www." in front of "dk" allowing it to resolve. Although the root DNS zone (the implied dot at the end of DNS names) can have A records in it, the current policy only allows A records for (some) nameservers. As a result, the new gTLD program, for example, does not currently allow "bareword domains" because you can't put an A record for the domain by itself in the root zone. (The policy doesn't allow an MX record, either, so email to someone@shop wouldn't be possible without a policy change.) The policy is aimed at keeping the root zone simple, and minimizing the volume of changes.
You're right -- dk. has an A record. It's coming from the dk name servers, though, not from the root zone. (I should have run the query the first time.) You're also absolutely correct that dk and www.dk resolve to different IP addresses. So the root name servers are returning a redirect to the dk name servers, which are providing an A record. (You can see it with "dig +trace dk.") The dk name servers can return whatever they want. I believe the behavior is undefined, though -- where a zone and a parent zone have records in common, they should be consistent. So you may get different behavior from different resolver implementations. (This may help to explain why some people see something at http://dk and some don't.)
both of this links "worked" for me, only one of them took me to the product directly, the other took me just to the homepage with Kindle suggestions instead of the suggestions served up by http://a.co i'm guessing that's what you meant.
IANA blocked registration of most of them under gTLDs (.COM, .NET, etc.) in 1993, on the thought they may be useful to support extensibility of the DNS down the track. Country-code operators have typically followed that lead as good practice.
As they were never really used for that purpose, slowly but surely they have been released into circulation. The applications by registry operators to lift the one- and two-letter domain restrictions are at http://www.icann.org/en/resources/registries/rsep
You can have zero character domain names. Briefly trying out a few of the country TLDs, the one for Anguilla works: http://ai. the trialing dot is not needed but helps tell your browser not to try to expand it further.
Many TLDs do not resolve, though many others resolve to the TLD's registrar's site.
A TLD can have an A record, so in theory you could have a "0 character" domain. You could also use it for email, so a@co would be a valid email address if co. had an A or MX record associated with it.
*Unless the original URL is less than 22 characters, in which case they conveniently _lengthen_ it for you. Which includes many of the unshortened links I post. I even recently set up my blog so posts have a ~9 character permalink. So twitter would award me with about a dozen bonus characters.