(oops, should have been a comment)
The Chicago Manual of Style says:
"The most common short form consists of the last name of the author and the main title of the work cited, usually shortened if more than four words."
Right now, we can't actually shorten the title, but the forum poster is incorrect in asserting that the short form should not contain the title unless there are multiple books by the same author.
As noted at http://forums.zotero.org/discussion/331/, repeat citations (cited before, but not the same as the previous citation) need to be supported as well, not just ibid (same as previous):
Only the first time a source is cited is the full citation used; each subsequent citation uses as little information as possible, usually last name and page number, or full name if more than one author with the same last name, or name and title if author wrote more than one source.
