The meaning of TMI is “too much information”.
It is used in situations when someone shares too many unsolicited details, and we want to motivate them not to repeat this mistake of being overly graphic again.
“Tmi” was created during the end of the 1990’s and the beginning of the 2000’s, when people were obsessing with the newly available mobile technology, as well as the opportunity of sending SMS messages.
It was this timespan, that saw the creation of several slang abbreviations, such as “tmi”.
The contraction was massively popularized by the explosive spread of the internet and social media sites like MSN, and later Facebook.
It was first defined on Urban Dictionary in 2002, which marked the unofficial adoption of the abbreviation into the English lexicon.