It doesn't have to be about relationships - I have Facebook for that. An audience can be useful and a lot of fun. I get thoughtful responses to questions I posit and random insights that have affected my thinking. There's some off the wall stuff and that can be fun too.
I think Twitter has a perceived high barrier to entry. If you don't have any friends on it, why would you tweet to yourself? And if you don't tweet, why would anyone follow you?
I've made some useful/interesting local connections and a few friends on Twitter. I think it can be useful for niche interests, be it hacking, food or music. The problem is that users need to be patient and discerning in developing a good list to follow. I've found much more value in finding new contacts on Twitter and more in maintaining distant relationships on Facebook.
Between the employer and my own contributions (about 50/50) costs are 5k USD/year for health and dental. I have a 1200 deductible that is paid by my employer 100%. I see a couple of specialists and can see anyone at any time. That embodies my appreciation for the US system.
I think Twitter has a perceived high barrier to entry. If you don't have any friends on it, why would you tweet to yourself? And if you don't tweet, why would anyone follow you?
It's all about who you follow, IMHO.