This blog post is currently featured on all network sites' community bulletins. As per this staff post, only those posts that have the announcements tag are supposed to be featured across the network:
Blog posts tagged "bulletin" appear in the sidebar on sites that are considered technology sites (based on the sites listed in the footer) but not on others.
Blog posts tagged "announcements" appear everywhere on the network (except on international sites).
There's a third for "stack-overflow" which only appears on Stack Overflow unless it also has one of the other two tags.
We also have an "international" tag for blog posts written in other languages and that can be paired with a language tag to cause the post to appear on the Russian, Spanish, Portuguese or Japanese SO sites
The post doesn't have any of the tags that would result in it being featured on any subset of sites in the network. The post has one category at the top, "community", and three tags at the bottom, "april fools", "copying code", and "data science".
Why is this blog post featured on all sites, even though it doesn't have the tag "announcements" or any of the tags mentioned in the above quote? Was the announcements tag mistakenly added on initial publication but removed later?