Redistribution vs use

[Julien Stern]

Dear all,

This is not about a new license, but questions about
existing ones. If this is not the right mailing-list,
please accept my apologies and ignore.

All the opensource licenses talk a lot about _redistribution_,
but not so much about _use_. However, it is not always obvious
(to me) which is which. I would appreciate having clarifications
on the following scenarios

Scenario 1:
A webmaster grabs an opensource software, say a perl guestbook,
modifies it so that it fits his needs, and start making his
users pay for the use of the guestbook (arguing that he does not
charge for the _guestbook_, but for the server, the storage
and the bandwidth). 

Is it ok?
Can he keep his modifications secret?
Does he have to display on his web site the copyright notice
of the original program?

Scenario 2:
Just the same but the application is in java. Technically
speaking, this is not a use anymore, but a distribution,
as the java applet is transferred to the user computer to
be executed. Is it considered as such and does it change
the answer of any of the above questions?

Sincerely,
Julien Stern