IMHO

from Jargon File (4.4.4, 14 Aug 2003)

IMHO
 //, abbrev.

   [from SF fandom via Usenet; abbreviation for `In My Humble Opinion']
   "IMHO, mixed-case C names should be avoided, as mistyping something in
   the wrong case can cause hard-to-detect errors -- and they look too
   Pascalish anyhow." Also seen in variant forms such as IMNSHO (In My
   Not-So-Humble Opinion) and IMAO (In My Arrogant Opinion).

from The Free On-line Dictionary of Computing (8 July 2008)

IMHO
IMAO
IMNSHO
IMO

   <chat> (From SF fandom via {Usenet}) In My Humble Opinion.
   Also seen in variant forms such as IMO, IMNSHO (In My
   Not-So-Humble Opinion) and IMAO (In My Arrogant Opinion).

   [{Jargon File}]

   (1998-09-24)

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

IMHO
       In My Humble Opinion (slang, Usenet, IRC)

[email protected]