/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.