I've become a bit disheartened by the site recently.
Many duplicate questions are slipping through without being identified as duplicates.
What's worse is that it seems there's a few users that rush in and instead of identifying it as a duplicate are happy putting any answer down in the effort to get points on the board rather than a correct, well thought out and well structured one.
Is there anything we can do as a community to improve this?
A few thorts.
My feeling is that the users you describe come from the dog-eat-dog world of Stack Overflow, where such "get in quick" behavior gives the bottom 95% of users a fighting chance of earning some rep.
If we respond the way the Stack Overflow crowd does, we would be downvoting much more than we do. Most of us downvote rarely, and I think we should continue that way.
So what to do? I suggest that if we were to upvote the better answers more often, the new users would learn what gets the rep and behave accordingly. If the top 20 regular contributors, or maybe even everyone who's been a member for a year, were to do this then this would be a lot of upvotes. Because Cycling answers tend to be opinion based, as a group we don't upvote much. An example of our behavior is this answer from Batman. A good solid answer, but only one upvote.
The problem is how to spread the message. Not everyone would agree to do it, and some would oppose the idea. Maybe we could put together a wiki post with a title like "Spread positive karma" or some such, then we could add a comment with our upvote, like "+1 Solid answer. [Link to the wiki post]".
If you can think of a less group-hug title for the wiki post, then all the better.
Its hard - I generally try to do it by memory if a question is a duplicate, given that I don't ask many questions myself.
Unfortunately, its somewhat of the nature of the site -- most bike problems are simple (99% of the time, the right answer will be either inflate your tires, check if your rear derailleur is bent or mis-adjusted or bikes are sized differently so you shouldn't buy that bike online). People could search the site and mark duplicates if they wanted to, but that seems like boring menial labor to me.
One thing to do would be to have a community wiki of commonly asked questions and just lump all the answers in there. Other sites have this as a "big-list" type tagged question, but it might be somewhat useful here. Then again, someone would need to check the big list, unless it comes up for them somehow. But then again, if most people searched their problems on the Park Tool repair site or Sheldon Brown, chances are they wouldn't have anything to post about anyway.
Another thing to note is that Bicycles.SE does not attract a lot of repeat question-ers. So a lot of people ask 1 question or 2 questions, get their answers and leave. Unlike Math.SE, there isn't enough question noise to bury duplicates either.
