There's a lot of space dedicated to explaining the difference between SO and PSE, but precious little cogent justification. I can't see any reason to have 2 separate sites. You're decentralizing information and forcing people to search in two places to find answers to questions that might or might not be considered subjective.
I'm sure you've read Joel's blog post Merging Season which addresses this point, although it's pretty open ended. But the important take-aways are:
- The delicacy of the balance is known to the community managers.
- The list of proposals that, according to Joel, fit well within Programmers contains many that would not fit inside StackOverflow, and few that do.
In addition, check out the top tags on Programmers. career, programming-languages, learning, software-engineering, productivity. Compare this to the top StackOverflow tags - nearly all related to platforms and languages.
Most of the popular langauges are top tags on Programmers as well, but look at the difference between the stream of Programmers Java questions vs. StackOverflow Java questions. I'd say seeing an obvious difference in the question streams alone is a good indication that the division between the sites is working.
Not only that, but there are WAY more people out there answering questions on SO than on PSE - so migrating a question to PSE is really a kiss of death. Case in point - I asked this question on SO, and very quickly got 8 very useful answers. Then someone did me a "favor" and migrated my question to PSE. Question is now effectively dead, with almost no views. 5 of the people who answered my question don't even have PSE accounts, so I can't ask them questions in the comments.
Actually, only 2/8 answers have a higher score than 1, and one of them was posted after the migration.
As for the question being dead, you can't blame that on Programmers. Questions die on both sites. If anything, any question has a higher likelihood of surviving the first few minutes, let alone hours, on Programmers than on StackOverflow.
If I had asked the question on PSE in the first place, I would still be waiting for answers.
I find this argument completely silly; there are 22 questions with no upvoted answers on Programmers out of 8606, (0.25%), and out of 1503865 on SO, 2730108 (18.1%) with no upvoted answers and 101104 (6.7%) with no answers at all.
Why? Why not just have a "subjective" tag, and let people who don't want to read subjective questions ignore them?
This is not a solution - who is going to do the work of making sure that every question that would have fit on Programmers is tagged subjective. What is subjective is also subjective itself - it's not always obvious what is a subjective question.
Based on the votes and comments to my answer to that question (+24 at this writing), it appears that the community is generally unhappy with the SO/PSE split.
Programmers has 160+ users with >2000 rep and growing. Score on a meta post means little at this point.
Please, whoever the powers-that-be are who run this site - I really think you have done the programming community a big disservice by splitting PSE from SO. Please will you seriously consider eliminating PSE and merging all the questions back to StackOverflow, where they belong.
The best distinction between the two can be summed up in this beautifully concise answer by Robert Harvey. In it, he compares fundamental knowledge to "ephemeral" knowledge:
Fundamental programming principles and techniques are eternal.
StackOverflow is literally filled to the brim with "ephemeral" problems and solutions. These fundamental principles, that will last with us long beyond Java generics syntax, CSS-3 box shadows, PHP frameworks, deserve their own site.