Announcement lists and release notes have an air of authority or finality, so people are inclined to only talk about things after the paint dries. That can be challenging for keeping up with a project on a continuous deployment model like the OSM database.
Kind of along the same lines, the U.S. community has been trying to move some of our institutional knowledge and decisionmaking out of OSMUS Slack and onto this forum and the wiki. To keep the left hand talking to the right hand, we jury-rigged a system so that any time someone posts a new topic on the forum, proposes a new tag, or changes a wiki page that represents an important local community policy, it gets cross-posted to a Slack channel automatically. (I think OSM World Discord has something similar set up.)
For example, we have a #highway-classification channel on Slack where we debate that evergreen topic as it applies to individual cases. We use this wiki page as a source of truth regarding each state’s policy. Any time someone modifies the page or links to a new state-level proposal, the diff shows up in the channel. On occasion, someone will get out ahead of community consensus; this integration helps us address any misunderstanding early before it gets out of hand. We all know how stealth edits to the wiki can take on a life of their own.
The “secret sauce” to this setup is the RSS feeds that both Discourse and MediaWiki generate. These feeds are noisier, less of a faît accompli than the things you read about in an announcement list. But any data consumer whose issue tracker isn’t already enough of a firehose can set up something similar.
For a more polished solution, the operations team is working on installing the DynamicPageListEngine extension on the wiki. This extension will allow us to set up a custom RSS feed for any page based on a template maintained by wiki users. You could imagine a less noisy “Changelog” page that comes with a more digestible RSS feed, and maybe a similar page that pulls together tagging news. The idea is to provide yet another mechanism for staying informed about the database, with a minimum of maintenance overhead. For data consumers, it would still be less authoritative and predictable than a customer-facing delivery note for a quality-controlled quarterly release of the planet, but hopefully busy developers will be able to regain some confidence in their own secret recipes.