One thing I would favour, is the ability for a node author to reset the rating of individual node back to zero. (At least of they were in positive territory).

The idea being, that if an author posts a node that later posts (or private messages) show to be answering a different question, seriously incomplete, or just plain wrong, then the author can update the node to reflect that, and zero the rep.

There have been (a few:) posts of mine where I have made one or more of the above errors. At that point you are faced with several choices:

1. Go back and update the node pointing out the error and giving a correct solution.

   That's fine, but it doesn't undo those votes already cast by people who also didn't see the flaw.

   It might also encourage the sending of prvate messages by those downvoting a node stating "I'm downvoting this node because..." or even just "/msg author [id://pqrstu|Total bollocks!]" giving the author the opportunity to "do the right thing".

   Especially gauling for those that posted the correct solution, but didn't gain as many votes because they posted later; or the do not have the same level of name recognition.

   Worse is that some later viewers will view the node and up vote the correction, despite that it may replicate a solution posted (correctly; first time) by a later node. Or simply because the author corrected himself.

2. You can post a note at the top saying that the solution is total crap and should be ignored.

   Even this will receive upvotes--on the basis of honesty I assume.

   It doesn't undo the votes cast by people who also failed to see the flaw in the solution.

   I've even added a specific note: "Stop upvoting this node; IT IS WRONG!". And still the node continues to garner upvotes, presumably for similar reasons?

3. Leave the node unmodified and hope that later voters will see the later corrections and either not vote, or downvote to compensate for the earlier mis-directed upvotes.

   Unfortunately, people (me included) have a tendancy to upvote a node immediately we read it, if we (think we) see a clever, insightful, or complete solution.

   If we then read the later post, that shows us that we too missed the flaw, there is nothing we can do about it.

4. Finally, a frowned upon practice, is to erase the node entirely.

   This has two advantages.

   1. Such nodes usually receive a comprehensive pounding. As such, it effectively undoes any earlier, misconceived upvotes.
   2. It removes the errant information from the thread, thereby preventing the very real possibility that those coming along later looking for answers to the same problem, will not be fooled by a wrong answer that managed to garner and retain enough votes that, when sorted by reputation, still appears well up the order relative to later, correct posts.

If I had the option to zero the reputation of a node, which would include removing it established reputation from my overall tally, there are several occasions I would have used this.

In addition, the post should probably gain some (preferably automated) headnote stating that the author has voluntarially withdrawn the node and relinguished any XP it had gained him.

It would probably also make sense to then freeze the XP of the node at 0 (and display it as such regardless), so as to prevent the node from gaining "sympathy votes" on the basis of honesty.

Though I can see some arguing that this latter idea would prevent them from further penalising a node.

It might even encourage the practice of the sending /msgs to the effect of "I downvoted this node because ...", or even "/msg author [id://pqrstu|Total bollocks!]" thereby giving the author the opportunity to do the 'right thing'.