Even the IndieWeb website doesn’t do a great job of explaining what it is, or what it means to “join the IndieWeb”. As far as I can tell, it’s a collection of practices and technologies that connects independent blog-type websites together into a quasi social network.
In discussing micro.blog and the #indieweb, Jason makes a valid point which others, and myself, have echoed. Social networks are so ingrained, so easy and so obvious that people don't need to think about them. It's by design, of course - make them sticky, make them frictionless.
To have to put real effort into what you are doing and actually adopt a philosophy for how you engage on the web is further than many are willing to go without having a real sense of why they should or what benefits they might gain from it.
As much as the technology needs to be easy to use the rationale is, perhaps, more important.