from
The Collaborative International Dictionary of English v.0.48
Ob- \Ob-\ [L. ob, prep. Cf. {Epi-}.]
A prefix signifying to, toward, before, against, reversely,
etc.; also, as a simple intensive; as in oblige, to bind to;
obstacle, something standing before; object, lit., to throw
against; obovate, reversely, or oppositely, ovate. Ob- is
commonly assimilated before c, f, g, and p, to oc-, of-, og-,
and op-.
[1913 Webster]
from
Jargon File (4.4.4, 14 Aug 2003)
Ob-
/ob/, pref.
Obligatory. A piece of {netiquette} acknowledging that the author has
been straying from the newsgroup's charter topic. For example, if a
posting in alt.sex is a response to a part of someone else's posting
that has nothing particularly to do with sex, the author may append
`ObSex' (or `Obsex') and toss off a question or vignette about some
unusual erotic act. It is considered a sign of great {winnitude} when
one's Obs are more interesting than other people's whole postings.
from
The Free On-line Dictionary of Computing (8 July 2008)
Ob-
/ob/ prefix Obligatory. A piece of {netiquette} acknowledging
that the author has been straying from the newsgroup's charter
topic. For example, if a posting in alt.sex is a response to
a part of someone else's posting that has nothing particularly
to do with sex, the author may append "ObSex" (or "Obsex") and
toss off a question or vignette about some unusual erotic act.
It is considered a sign of great {winnitude} when one's Obs
are more interesting than other people's whole postings.
[{Jargon File}]