Didn't someone already ask that? Yes, something like this has been asked and I'll provide a link for you right here, before you have to go looking for duplicates: Why is Stack Exchange split into multiple sites? In that case the OP asked about why there are so many splits. This isn't my question.
My concern is not so much about providing more sub-sites, but the way overlapping questions are handled right now. It appears every site moderator just keeps looking to find something wrong with the next question or answer she can find and will vote to close the entire thing or at least down vote it.
I understand if its really off-topic, sure close it, shut it down, make it go away, but if it's just not fitting perfectly into someones own expectation of what this exact site should be about, but other people appear to happily exchange knowledge there anyway - telling them off and closing their topics appears counterproductive and doesn't help anyone.
For example there is a site about Earth Science and one about Outdoors, one about Travel and another about Aviation, one for Health, one for Fitness, one for Sports, one for DIY home improvement and one for Crafts and one for Lifehacks.
Yes, these categories can be differentiated, but not all questions will fit exactly into one of them or can easily be asked on multiple boards at the same time (my point here).
Just like we don't have one site for Python, one for C++, one for Java, how can we justify having one site for Academia, but another one for Biology and another one for Physics and a third for Chemistry and another one for Mathematics?
What is the guy with a question about chemical equations regarding his biology experiment going to do? First, he'll try in Biology, because, you know, that's his comfort zone, but he'll be directed to go somewhere else. Then he'll try in chemistry, where he'll be told it's too mathematical a question. Then he'll try in Mathematics, where someone things this is all about general science.
See, topics can not just be categorised into small little sections and split that way - it's insane - there are interdisciplinary questions everywhere and the current direction Stack Exchange is taking is killing them off.
Yes, you can vote down and close this one, too, since it's becoming more of a complaint than a question, but I sincerely hope someone will please turn this around and see that Stack Exchange was all about bringing people together and not splitting and disecting them into smaller and smaller categories.
Don't get me wrong - I love Stack Exchange - I just don't love when people disregard valid and well written answers or questions, because they don't fit into their exact topic expectation.
Please let me know if you disagree (I am sure many people will) and why? And if you need a proper question:
Is splitting Stack Exchange into tiny sub-sites really the direction we should be taking?
My suggestion is simple - just have bigger categories - merge those sub-sites, maybe even better:
Why not allow the users to vote to merge one Stack Exchange site into another? I think this would be fair and the right approach, because it'll be a community decision, by the people who actually want to use these sites.