Just to clarify, you mean "Command" + "-" nad "Command" + "+" as shortcuts for the backward and forward buttons that are visible on the entry details page?
JoeSwann I would think it would be useful to go chronologically forward and backward in the set of found entries. So, if you are looking at all entries you simply step through day-by-day, but if you have filtered on, say, a tag or are looking at "on this day" you would jump forward and backward entry-by-entry.
This would be a separate feature request and I think it has been discussed in the forums in the past, but I can't find the post at the moment