There have been many occasions previously when Facebook did something that was really fast - Beacon, profile redesigns, moving apps onto separate tabs, etc. etc

There have been many occasions previously when Facebook did something that was really fast - Beacon, profile redesigns, moving apps onto separate tabs, etc. etc. - each time there was a lot of bad publicity and some high profile account closings; in the long-term it didn't do anything to slow down Facebook's growth. I am not saying that there can never be another social network that knocks Facebook out of #1, but bringing back features or privacy settings that Facebook dropped in favor of long-term growth is not the strategy that will bring about that kind of change.