What kind of login?

Looking on openSUSE wiki, and Wikipedia. One with login, the other without. They had login too and the site was small. Then they removed login, and site started growing to its present size. How many people will go trough registration process, just to make minor edit? I think just a few. I edited Wikipedia few times, with login requirement it would be no edit at all. So, what is what we want? Protected site or active one? Fear from vandals? Wikipedia has same problems, and obviously some solutions. We can have some pages protected, some accessible with login and the rest free. -- Regards, Rajko M.