What was the difference between Jerusalem's honorary primacy and the primacy of Rome, Alexandria, and Antioch? In Church History in Plain Language, 144, Bruce Shelley writes about the "primacy" that certain bishops enjoyed in the early church:


  The Council of Nicaea recognized the bishops of Alexandria, Antioch, and Rome as preeminent in their own areas.  Jerusalem was granted an honorary primacy.


It seems that Jerusalem's "primacy" was somehow different from that of the other three cities mentioned here.  I'd like to know, practically speaking, what was different.  Was Jerusalem's bishop "preeminent in [his] own area" in a way similar to the others?  Or was it a "primacy in name only," which for practical purposes meant that he was expected to submit to the bishops in nearby Alexandria or Antioch?

An answer that complements its analysis with an example or two of how these bishops and churches interacted in the fourth and fifth centuries would be especially interesting.
Canon VI of the Council of Nicaea says, among other things:


  LET the ancient customs in Egypt, Libya and Pentapolis prevail, that 
  the Bishop of Alexandria have jurisdiction in all these, since the like is 
  customary for the Bishop of Rome also. Likewise in Antioch and the 
  other provinces, let the Churches retain their privileges. 


Canon VII says:


  SINCE custom and ancient tradition have prevailed that the Bishop of 
  AElia [i.e., Jerusalem] should be honoured, let him, saving its due 
  dignity to the Metropolis, have the next place of honour. [my emphasis]


The General Introduction to The Works of Saint Cyril of Jerusalem, Volume 1 (page 14) puts this in perspective, proposing that the seventh canon of Nicaea merely reasserted that Jerusalem was subject to Caesarea, "while also confirming to Jerusalem certain unspecified ancient privileges."

F.J.A. Hort (Two Dissertations &nbsp;59) is cited on page 15:


  All Palestine was subject to the supremacy of Antioch; and the metropolitan jurisdiction of Caesarea over the rest of Palestine was balanced by privileges peculiar to Jerusalem.


In strict terms of hierarchy, Jerusalem ranked below Caesarea and then Antioch, but, because of tradition, enjoyed privileges that otherwise were only enjoyed by Alexandria, Antioch and Rome.