Leaps and bounds separate that which is ironic and that which many people simply say is ironic. Christopher Warner wants to set the record straight: Something is ironic if and only if it is the exact opposite of what you would expect.
Irony is a rhetorical device, literary technique, or situation in which there is an incongruity between the literal and the implied meaning. No written method for indicating irony exists, though an irony punctuation mark has been proposed. http://en.wikipedia.org/wiki/Irony
'Isn't it ironic?' You hear it all the time - and, most of the time, actually no, it isn't. Hypocritical, cynical, lazy, coincidental, more likely. But what is irony? Zoe Williams meticulously, sincerely, and unironically hunts it down. http://www.guardian.co.uk/theguardian/2003/jun/28/weekend7.weekend2
Irony may be defined as the conflict of two meanings. http://xtf.lib.virginia.edu/xtf/view?docId=DicHist/uvaGenText/tei/DicHist2.xml;chunk.id=dv2-70