Proposals on being closed as duplicates have the following message :
This proposal would tend to drain audience from an existing Stack Exchange site.
What is the threshold for deciding whether a proposal will drain audience from other sites ?
Some of the proposals closed with this reason had 30-40% of followers that were following only that specific proposal.
Is this not enough ?
Duplicates are not determined by the number of people who use related sites (or follow other proposals). Duplicates are determined by the scope of the subject and the example questions being asked.
There's a blog post covering how we divide and scope sites:
That blog post has become a bit dated. We've evolved and refined our criteria for what constitutes a "duplicate site." The basic premise is "if the community is already being well-served by an existing site, the proposal is likely to be considered a duplicate." In other words: "does the proposal add anything new to the network?" We don't generally want to create vanity sites where folks want their own site splintered off just because.
But those are broad generalities that don't comprehensively describe all situations. It's preferable to discuss duplicates based on the their individual circumstances and merits.
