Until now when the user was in any place of the portal clicked the "Sign in" link he was shown a default portal login page. Of course it was already possible to create your own customized login page using the available portlets, but the user was not redirected there when clicking the "Sign in" button.
After this improvement it is possible to let the portal know that a given page should act as the portal login page by setting a property in portal(-ext).properties. For example to set the home page of the guest community:
auth.login.url=/web/guest/home
But that's not all. It's also possible to have a customized login page per community. That will allow users that are navigating a give community site to log in without going to a portal wide page. The way to achieve it is super simple and doesn't even require modifying a properties file. The community administrator can do it himself by just creating a regular community page and giving it the /login friendly URL. That's it, the portal will automatically detect such a page and will make it the login page for that community. Of course, don't forget to put the actual login portlet there :)
I'm trying to keep my blog posts short, so I've created a wiki page with more details about this functionality. Also a wiki page is better to document this feature since it can grow if more features are added. You can find it here: Customizing the portal login page.

