Q:

Does apt-get purge remove reverse dependencies?

Suppose we sudo apt-get purge mypackage.
If mypackage, which is a dependency of yourpackage, is installed at the time that we purge mypackage, is mypackage also removed?

A:

A simple test will answers you:
$ apt-cache depends vim
vim
  Depends: vim-common
  Depends: vim-runtime
  Depends: libacl1
  Depends: libc6
      ......

Now as you can see the package vim depends on vim-common. So let's try remove the package vim-common:
$ sudo apt-get remove vim-common 
Reading package lists... Done
Building dependency tree    
Reading state information... Done
The following packages will be REMOVED:
  ubuntu-minimal vim vim-common vim-tiny
0 upgraded, 0 newly installed, 4 to remove and 2 not upgraded.
After this operation, 3,268 kB disk space will be freed.
Do you want to continue [Y/n]? 

Take a look on the line:
The following packages will be REMOVED:
   ubuntu-minimal vim vim-common vim-tiny

So as a conclusion removing a package will cause to remove all packages that depend on it.

