What support "contract" should decoupled extensions have with their users? Same as CMS?
When or how do we decide it's no longer viable to support this extension?
Let's say the Joomla 3.x is supported until 2018 (to make a number). If we decide to retire com_weblinks in 2016, it would mean that the user had to switch to another extension and doing a migration of the data. The support promise we give to the CMS suddenly can be thrown to the bin then because it doesn't mean anything anymore if the user has to migrate extension data within a major series.
I think it's crucial that core extensions share the same support as the CMS does. If we ever want to retire an extension, it should only be done at the release of a major series.
I agree with @Bakual. A core-supported extension that exists within the 3.x series should be supported for the life of the series. If at the start of the next major version it is decided that we no longer will continue development, then support "stops", but the code must remain available until the 2 year support period is fully expired. After that, unless there is a compelling reason to remove the code, I say leave it up and available for the stragglers who lag behind a couple versions.
Ok, so I've added some notes here -> https://github.com/joomla-extensions/weblinks/blob/master/CONTRIBUTING.md#version-strategy
If you want to change anything, PR away.