My thoughts on the questions:
How many Queens on a board
This is a variation of the eight queens problem, but there's no way to make that connection without trying to search on Google. The linked question doesn't point out the original puzzle either. That's a problem for two reasons:
Experts tend to care about the history of their craft. This is an interesting variation on the original problem, to be sure. But the puzzle is more interesting when you know about the source. This version seems a bit arbitrary.
There's no way to find this question if you are looking for variations on the 8-queen problem.
The second consideration makes me doubt the self-evaluation results:
Net Score: 14 (Excellent: 21, Satisfactory: 24, Needs Improvement: 7)
I'm curious what search terms people used to come up with an Excellent evaluation. Most of my searches actually turned up this Stack Overflow question (which isn't exactly spectacular either). Only when searching the exact wording of the question, did I find this question. And even then, it was below the Wikipedia article I linked to above. Needs Improvement
The Old Millionaire
Doing a quick search of the title, I found this droll cartoon:
That's not exactly the same puzzle though. Thankfully, the OP commented:
When knights and knaves meet the Monty hall... – warspyking Oct 21 at 18:08
If you are looking for a mashup of the Monty Hall and knights and knaves puzzles, this question shows up in Google near the top result. With that little bit of background, this becomes a very interesting (and findable) puzzle. It also seems novel. My vote: Excellent
Net Score: 14 (Excellent: 21, Satisfactory: 22, Needs Improvement: 7)
3D wooden puzzle
The answer helpfully notes that this is called the Burr puzzle. Unsurprisingly, this question doesn't show up in Google searches. My guess is that with an edit of the title it would. Needs Improvement
By the way, this is a fine example of an identification question. While some sites encourage these questions, they have limited value.
Net Score: 14 (Excellent: 20, Satisfactory: 29, Needs Improvement: 6)
Crack the Code #2
Very generic title; I didn't bother with a search. Needs Improvement
Net Score: 6 (Excellent: 15, Satisfactory: 30, Needs Improvement: 9)
Ship and stone puzzle
I immediately found other versions online: The Brick, The Boat and The Lake and Will there be any change in water level/height of floating part of the boat if stones are dropped into the pond from a floating boat?. The Puzzling.SE version is perhaps a bit cleaner, which is good. Typically, this would be an Excellent in my book, but I have a nagging suspicion that one of the other variations should have been credited as the inspiration
Net Score: 3 (Excellent: 20, Satisfactory: 20, Needs Improvement: 17)
Crack the Code #4
Ok. Another in the series I mentioned before. Ho hum. Needs Improvement
Net Score: -2 (Excellent: 10, Satisfactory: 18, Needs Improvement: 12)
Knights and knaves in a foreign language
The answer identifies this as The Hardest Logic Puzzle Ever, so I'd call this a chestnut. A better question would cite the original formulation and find some way to add value to what you can already read on Wikipedia. Failing that: Needs Improvement
Net Score: -3 (Excellent: 11, Satisfactory: 22, Needs Improvement: 14)
Who is the killer
Ugh. Needs Improvement
(As an aside, "abcdefghijkmnopqrstuvwxyz" is a surprisingly popular title for YouTube videos.)
Net Score: -4 (Excellent: 14, Satisfactory: 20, Needs Improvement: 18)
What is the number 4.9292683…?
Well, this question turns up right away when you search for the number. But so does the Inverse Symbolic Calculator Plus entry, which is certainly the more useful result. All in all, I'm going to go with Satisfactory since it does provide a general solution to this sort of problem.
Net Score: -8 (Excellent: 14, Satisfactory: 20, Needs Improvement: 22)
Puzzle of Random Numbers
While it's damned easy to find this question if you were presented with the same message, the odds are you won't find it if you are faced with a similar cypher. Needs Improvement
Net Score: -15 (Excellent: 10, Satisfactory: 19, Needs Improvement: 25)
Overall, my evaluation is much lower on most questions than the community's view. Part of the issue might be that I'm weighing this bit of criteria:
Run comparative Google searches on these questions and see if the content is better or worse than what is already out there on the internet. Are the answers correct, clear, useful and informative?
More heavily than this bit:
Would the question and answer be interesting to the kind of user this site is trying to attract?
In my judgement, based on this sample 90% of the questions are disposable. What I mean is that they will provide some entertainment when they are first posted and after a day or two be lost deep in the question list never to be read again. It's a fine line between long-tail questions and no-tail ones.
One of the ways we measure that difference is by looking at how much traffic comes via search engine. We are looking for something like 80% on a healthy site. At the moment Puzzling is at 18%. Now that should increase over time as more and more questions are asked in indexed by Google. But I'm concerned that this site has become too dependent on flash-in-the-pan questions that pop up in the hot questions sidebar on other sites for traffic.
I'm also concerned that so few questions acknowledge the debt they owe to existing work, titles are generally poor, and so many questions are minor variations of previous questions. I'd love to see more people take ownership of the content on this site by improving it when possible and downvoting it when not.