As far as I can tell, adding Dependencies to a module allows other elements you choose to access the parameters you set for the module.
Say for example you are creating a module/plugin/snippet combo. You want to set a path, which all the components need to know to function.
1. Create the snippet and plugin first, so they will be available in the selection list later.
2. Create the plugin, on the Configuration tab, check the "Enable Parameter Sharing".
In Module Configuration input add this:
&Path=Path to xadmin;text;assets/modules/xadmin/
Save the module.
3. Once back at the modules list, open the module for edit.
4. On the Dependencies tab, click Manage Dependencies.
5. Add your snippet and plugin on this screen, and save.
Now you should have the $Path param available to all the components. You can go echo it out in your scripts to verify.
$Path=’assets/modules/xadmin/’;
Param format is this: &Path=Path to xadmin;text;assets/modules/xadmin/
&Path= (Name of the param)
Path to xadmin; (Label for the Config tab)
text; (denotes the type)
assets/modules/xadmin/ (param value)
Hope that helps a little, thats as far as I got