Obligatory Link :-)
Interesting...
Let's turn this into a link in which the meaning of the prefix Ob is explained. Ob is a short form for obligatory and originated in USENET discussions and Internet mailing list discussions in which an individual was intentionally posting a message that strayed from the topic of the newsgroup or mailing list. In order to mitigate the fact that they had posted an off-topic message, the person would include a postscript to their message that began with a compound word beginning with the prefix Ob.
Thus on a mailing list about Wikis the postscript might look like the following:
At its best, the requirement to justify a link from some random subject back to the official topic can force novel insights. Rather like in poetry, where the need to form a rhyme can rule out conventional cliches and force you to be original. -- DaveHarris