gnus-subscribe-newsgroup-functions is a variable defined in `gnus-start.el'.
Its value is
nil
This variable may be risky if used as a file-local variable.
Documentation:
*Hooks run after you subscribe to a new group.
The hooks will be called with new group's name as argument.
You can customize this variable.
This variable was introduced, or its default value was changed, in
version 22.1 of Emacs.