"Remember what we are doing here. We are building a free encyclopedia for every single person on the planet. We are trying to do it in an atmosphere of fun, love, and respect for others. We try to be kind to others, thoughtful in our actions, and professional in our approach to our responsibilities." Jimbo Wales 16:49, 26 August 2005 (UTC) 
"Semi-protection doesn't block just anons- it also blocks new users. And having to wait four days really kills the whole wikiwiki thing." - unnamed person
And in some cases, the whole wikiwiki thing is more trouble that it is worth, by rather a long shot.