Hello Ivan. Your solution may work in some situations. I am aware of many programmes where, unfortunately, this does not work for a variety of reasons. One reason is that students can be on very limited bandwidth or on good bandwidth 'if only they can keep a connection'. This means they rapidly give up on clunky institutional logins with their multiple layers of privacy and login codes and head for something that works fast - like Skype (if available in their country). Another common reason is that students will use their company wikis - which sys-admins are highly unlikely to allow to be connected to any university site - or they use a Facebook group to which some (many?) universities will not link. The list goes on....! :)