"Since the early 20th century, literally has been widely used as an intensifier meaning “in effect, virtually,” a sense that contradicts the earlier meaning “actually, without exaggeration”: The senator was literally buried alive in the Iowa primaries. The parties were literally trading horses in an effort to reach a compromise. The use is often criticized; nevertheless, it appears in all but the most carefully edited writing. Although this use of literally irritates some, it probably neither distorts nor enhances the intended meaning of the sentences in which it occurs. The same might often be said of the use of literally in its earlier sense “actually”: The garrison was literally wiped out: no one survived."
"usage The use of literally as an intensifier is common, esp in informal contexts. In some cases, it provides emphasis without adding to the meaning: the house was literally only five minutes walk away. Often, however, its use results in absurdity: the news was literally an eye-opener to me. It is therefore best avoided in formal contexts"
I don't use 'literally' as an intensifier, but you can't really call it wrong when someone does.
"1. the humorous or mildly sarcastic use of words to imply the opposite of what they normally mean
2. an instance of this, used to draw attention to some incongruity or irrationality
3. incongruity between what is expected to be and what actually is, or a situation or result showing such incongruity"
So not the whole situation or what is said has to be the opposite of what is expected. Many coincidences can therefor be ironic, though maybe only to some. Like rain on your wedding day.
Inspired by this rage comic: http://www.reddit.com/tb/hmu6v. And many internet grammar nazi's <3.