Rands covers this pretty well in "The Update, The Vent, and The Disaster" [1], I think. Specifically, the difference between a "vent" and a "rant": "The Vent that wants no help is a Rant. The Ranter somehow believes that the endless restatement of their opinion is the solution. Perhaps they have no clue what a solution might be or how to find it or perhaps they’ve been stewing on the topic so long, they’ve lost all sight of logic."

[1]: http://randsinrepose.com/archives/the-update-the-vent-and-th...