This service converts email addresses into backwards domains starting with "com.inamidst.mbox" for the owner of the email address to use. See below for further details, including alternate ways to create these identifiers.
Usually, domain names are used in email addresses and HTTP URIs in the form "example.com", with the top level domain (.com, .net, .co.uk etc.) coming at the end. You may also have subdomains such as "myname.example.com", and very occasionally you see ridiculous examples such as "this.is.a.host.at.example.com".
Some systems, however, use these addresses—just the domain names, with no paths—as local identifiers. For example, the Java package-name convention makes use of this kind of identifier. Indeed, this service was written in response to a discussion about TAG issue siteData-36, one of the possible solutions for which is to use these reversed domain names as identifiers in HTTP header values.
The advantage that these types of identifier have over HTTP URIs is that they're much more compact. The disadvantage is that people are much less likely to own domains than they are to have, say, an email address. Domain names were used as part of the tag: URI proposal too, and the authors of that proposal got around it simply by allowing emails too. But in most other systems, this flexibility isn't possible. That's where this service comes in.
If you have an email address but no domain or subdomain, you can simply have a subdomain at this site that contains your email address encoded inside. You can use any one of three different variants of different length and obfuscation level.
This is powered by a CGI written in Python. It does require that you put your email address in, of course, which means that it'll show up in my server logs. I won't distribute or sell these addresses or anything, but if you still want one of these DNS IDs without divulging your email address, you still can. Simply download the source, save it as dnsid.py, and then run it a la ./dnsid.py name@example.org to generate the DNS IDs.
This was mainly written as a programming exercise rather than a service for heavy use, but anyone is welcome to use it as long as they don't expect hosting or any warranty etc. If you have any questions, do feel free to contact me.
Sean B. Palmer