Speaking of web servers, nginx is under the 2-clause BSD license
(http://nginx.org/LICENSE) and due to it being under a permissive license, it
can be deployed anywhere. I know that if it was under a GPL license, that the
BSD crowd would have a problem with it due to their freedoms being restricted
by the GPL.
I totally understand your worries about a permissively licensed piece of
software allowing others to make proprietary forks. In the case of nginx
again, as long as the standard nginx is free software, who cares if the
creator wants to create a custom modified version for a client as long as the
original is always free?
Don't also say that "well the creator can always change the license and make
it non-free" since that applies to GPL software as well.
