OT: Help decoding SPAMMER's encoding of my contact info

[Michael ODonnell]

I've received SPAM where my contact info has been
stored in a string encoded in (what I believe to be)
some simple-minded format that I'd like to decode.
I have reason to believe that this format is on the
order of rot13, or uuencoding, or base64, or some
other relatively straightforward transformation that's
probably familiar to those who do webby stuff.  Anybody
care to take a crack at it?  You'll know you've got it
if you come up with something that includes my email
address in the form of xxx at theworld.com where xxx=mod

The encoded string is:

 MTA2NDIwL21vZEB3b3JsZC5zdGQuY29tLy8

TIA for any time anybody cares to spend on this.