Just one more thing : You can't register
a nickname containing "space" in it. (that's
because the nickname may also be used for email)

But when you write a message, you are allowed
to put nickname in it and the software will
understand it.

Ie: When registering, you have to choose a
nickname like "YannStettler". But when writing a 
message, you can use "Yann Stettler" and nobody 
else will be able to use that name...

Cheers,
Yann Stettler