It involves effort, though - not much effort, but a little more than posting on Twitter, Tumblr or wherever; and this, it turns out, is sufficient.
> I fight hard to read the web in my way.
Turns out most people posting content don't want to fight hard to post it, and most people reading content don't want to fight hard to read it, and this is why twitter, facebook et al are big things, rather than everyone just having their own sites and decentralised syndication.
If something else is to take twitter's place, its barriers to entry must be at least as low as twitter's.