Jim, I wasn't referring to the TLD name (top level domain - the part after the dot) but what is sometimes referred to as the a registered domain name - like "techsurvivors" or "amazon". The country code TLDs are mostly 2 letters - but the registered domain names that are two letters are either all gone long ago (me.com was registered in 1994 - the world wide web as we know it now was in its infancy) or prohibited by some TLDs, like .info and now .org.
I'd love to know who owned me.com and how much Apple paid to get their hands on it. I'm sure it wasn't cheap!!
Some examples of two letter registered domain names that do exist and are in use:
rr.com (RoadRunner), ts.com (Tickets - UK outfit), mm.com (Minnesota Micronet...no, not the candy!), aa.com (American Airlines, of course)
There are also a lot of two letter domains that resolve/redirect to company names - they're acronyms of the company name. Eg: ms.com resolves to morganstanley.com, rs.com to rocketsoftware.com, etc.
And there are some that go nowhere - ua.com - and darned if I can figure out who owns it. It doesn't conform to Network Solutions' Whois Policy...(you just get Google if you try going there) Bet United Airlines would have liked to have that one! Now, of course, domain names are the least of their worries!
There are also probably a few "parked" - like bb.com, which is owned by an internet parking company called Thought Convergence. Obviously they want so much for the name that nobody has been willing to pay. And there are a few that some of the big boys probably wished they'd snagged - xm.com is NOT owned by XM Satellite Radio - it's domain is xmradio.com
Anyway, it's interesting - just like 3 or 4 letter domain names, the 2 letter domain name sites run the gamut of nonexistent (but the names are owned - they're ALL owned) to full-fledged major business sites. All the two letter domain names were first registered in 1993 or 1994, with the odd exception (xa.com wasn't registered until 1997 for instance).
OK - now I'll go and do something a little more useful!!