Inspired from BB code, sarcasm/sarcasm are used to denote sarcastic passages in one's text when their nature is rendered ambiguous by the inability of varying tone of voice or communicating exaggerated gestures, as would be the case in person-to-person conversation. This is especially useful when the said passages could easily be misinterpreted as offensive, dimwitted or otherwise unfunny. While perfectly acceptable on the internet, the use of "bracket sarcasm end-bracket" in day-to-day conversation is considered socially awkward and should be refrained from.
"sarcasmOh my! It appears as if the oil industry is once again taking initiatives to save the environment. They have our best interests at heart and never buy patents for ludicrous sums of money that would otherwise render their industry unprofitable./sarcasm
(Notice this is the end of the sarcastic passage and the beginning of the normally-read passage)