Mail art is a way that artists can share work with other like-minded practitioners all over the world - it is a wonderful way to connect with others, and share your work.  
Here are some of my submissions to others' mail art calls, and lots of links.  
Send your link if you'd like to be added here:
emtheartist (at) yahoo.com.
(you'll have to type it - I am hiding from the spam makers)

Links
Story in the local paper about the Library Show
See the Plainsboro Library
Cultural Crossroads Show

Mail Art Call
"La pluie sur le trottoir, le pavé" ou/et
"Les toits de nos villes, de nos villages"

Alyonka
Doors; 
Christine LeRoy
Galeri Seni - Malaysia
Ryosyke Cohen
Lots of Links
Dragonfly
Dream
Ray Johnson - started it all
Webring of mail art
Carla Cryptic
Keith Bates
Rosewitha
Immigration
Sputnik
Global Calls
Denis Charmot
Mailmania3
International UMA
Rico di Parigi
Thomai Kontou

1st International Mail Art Biennale in Greece

Mailartissimo Russia

 

c. Emily Townsend Studio 2007