IMO / IMHO

Definitions

IMO and IMHO are internet abbreviations meaning In My Opinion and In My Humble Opinion (or In My Honest Opinion), respectively. They are used to preface a statement as personal perspective rather than established fact, softening potentially controversial assertions in online discussions. Both abbreviations originated in early internet communication on Usenet newsgroups and IRC in the 1980s and 1990s, where text-only communication lacked the tonal cues of spoken conversation. IMO signals that the writer acknowledges their view may not be universally shared. IMHO adds an extra layer of modesty or self-deprecation, though some use it ironically before stating a strong opinion. The abbreviations remain widely used in forums, chat, social media, email, and professional communication tools like Slack. They serve an important social function in digital discourse by establishing that a statement is subjective, reducing the likelihood of confrontational responses, and promoting more civil discussion.
In plain English: Short for 'In My (Humble) Opinion' — a way of flagging that what follows is your personal take, not a fact. The 'humble' part is usually optional and sometimes ironic.

1980s: IMO (In My Opinion) and IMHO (In My Humble Opinion) emerge on Usenet newsgroups as conversational hedges
1990s: The abbreviations spread to email and IRC; debate arises over whether the H stands for 'Humble' or 'Honest'
2000s: IMO/IMHO become standard digital communication — so common that using the full phrase sounds oddly formal