Is there a website that unifies lemmy and mastodon?
Kbin does that in terms of function as in kbin has its own microblogging element to the experience, but it doesn’t do anything to bring the existing kbin and mastodon universes together.
Mastodon can do this. Mastodon interprets Lemmy communities as users, Lemmy threads as boosted posts with user mentions, and Lemmy comments as replies. If you search on Mastodon for a Lemmy community using the Mastodon format e.g. @community@domain instead of !community@domain you’ll find the community and posts.
I just wish browsing communities on Mastodon was cleaner. Instead of seeing posts to the community, you see every comment posted instead. If that aspect changed, Mastodon would be almost perfect.