Ah yeah, this makes sense.

I have seen other services include an explicit SSO link under the user/pass form, which IMO is clearer what’s actually going on, but I’m sure that structure hopelessly confuses lots of less technical users, too.

Yeah, I see this one happen occasionally, and it makes me marginally less grouchy.

I’m also finding it really effective. I only hate that backing out from a post is a crapshoot on whether it preserves my scroll position, resets to the top, or reloads the entire feed.