@nolan I blogged a little about the overlap a while back - https://doubleloop.net/2019/05/01/bridging-the-indieweb-and-the-fediverse-with-bridgy-fed-part-1/.
I agree they're complementary and I do both. I actually feel like they're converging on the same featureset, just coming from slightly different angles.
They were almost the same thing, too:
https://dustycloud.org/blog/on-standards-divisions-collaboration/