Thats ok, sef is a term given to urls that go from looking like this:
http://blah.com/index.php?option=com...&id=5&Itemid=6
to something more humanely readable like this:
http://blah.com/blog/my-artile-title.html
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Reading back your initial post, I think I may have misread it. Im afraid its not possible to redirect registrations to another page using Joomlas default login module. This maybe possible through a third party login module or community builder