When googling for information on how to do things, I often have to find my way among tons of garbage. There are two kinds of it: stupid sites and forums for wannabes (especially for ASP and ASP.NET, full of awful examples that cry for revenge) and high quality accurate - yet obsolete - docs and how-tos.
SO is very good at eliminating the first kind of noise; being relatively new, it hasn't faced information obsolescence yet. Will this change in the future and be a problem?
Some things are unlikely to change much, like "How do I move the turtle in LOGO?" Others change very often and, judging by the tags distribution, SO is mainly used for recent technologies.
In a year or two, will searches for ASP.NET MVC, F# and all "new" stuff tend to give obsolete answers?