The filibuster happens when a cloture vote fails and the minority that blocked the cloture vote has to keep talking.
The Republicans won't file a cloture motion because they think that sets a bad precedent....so a real "all night" filibuster won't happen, much to the dismay of freepers etc, unless the Republicans change their strategy and file a cloture petition.
That's interesting, do you happen to remember who said this?