I disagree with @JeffAtwoods answer for multiple reasons (in the same order as his points)
We don't believe in overly nagging and notifying people for minutiae. This is a core philosophy at the highest echelons of the company leadership. (Read: me.)
- So make it opt-in. Why not?
You should care about your question more than any other human being on the planet. If it is closed, you should already know about that without needing a special magic notification.
- I agree that I should care about the question, but I shouldn't have to keep refreshing the page.. Lets say I usually hang out at A.SE. I ask a question at B.SE. Now, being online, I'd naturally like to know about my question immediately. While on A.SE if I'm doing some stuff, I should get the B.SE close notification immediately without having to refresh the page. I care about my question --so much that I want to know what happened to it immediately.
It's an invitation to complain. "Oh look, here is a signed, notarized document telling you we closed your question." Cue Eeyore in 3... 2... 1...
- Its not just an invitation for complaining, it's also an invitation for improving the question. I've seen many crappy, closed questions get improved and reopened.
The existing close reasons on the question, along with the explanation, should be sufficient for explaining what is going on.
- This point is only valid if the OP realises that it was closed in the first place. Which is the object of discussion here.
As @TimPost said, this may not be appropriate for SO, where it would be rare to see any post without comments, especially a closed one. But, on the SE 2.0 sites, which don't have much activity, this is possiblethis is possible.