[tankenmate]

I think you'll find that IANA (currently ICANN) refuses to put general purpose A, and AAAA records in the root. As far as I am aware only NS, "glue" A (and AAAA), and DNSSEC records are allowed in the root (aside from the records necessary for the root itself, i.e. SOA etc).

You should also note that email addresses that doesn't have a '.' in the host part are technically invalid, i.e. me@mytld is not a valid fully qualified email address.

[icebraining]

I don't know what IANA decided; all I know is the TLDs I listed do have A records, and they load at least on Firefox, so there's obviously no technical reason the new TLDs can't.

You should also note that email addresses that doesn't have a '.' in the host part are technically invalid, i.e. me@mytld is not a valid fully qualified email address.

Hmm, has RFC 2822 been superseded? Because it clearly says the domain part can be a dot-atom, which is defined in the same RFC in ABNF form as:

    dot-atom        =       [CFWS] dot-atom-text [CFWS]

    dot-atom-text   =       1*atext *("." 1*atext)

As you can see, the dot (".") is enclosed in a section of variable repetition (*) with no minimum number of times, so it can not appear at all.

[tankenmate]

I suspect those A records are probably grandfathered and they are of course ccTLDs so the rules are different. None of the gTLDs have A records for their TLD (although they almost certainly have glue A records). From memory I queried John Craine (ICANN Security, Stability and Resiliency Director) about this a number of years ago and again if I remember accurately his response was that they wouldn't allow any additional types of records. I suspect this is a policy decision rather than a technical one.

RFC 2822 has been superceded by RFC 5322. The problem is not being allowed to put MX records in the zone for a TLD, and hence the mail is not routeable. Also remember that you would need to differentiate between "me@mytld<.localdomain>" and "me@mytld.", I'm not sure if all MTA software (let alone MUA) will do the right thing with differentiation. This is probably considered to impact stability and hence is discouraged.