An identical comment on an article is rejected by the system, regardless of who or when it is made.
Scenario: a personal site, author writes of the birth of first child.
Visitors all wish to offer congratulations.
Once one person makes a post containing only the word 'Congratulations', no-one else may do the
same. They would need to find an alternative.
See a small (not necessarily perfect) fix in patches forum
http://snewscms.com/forum/index.php?topic=7238.0
