Twitter is the ultimate service for the mobile age - its simplification and constraint of the publishing medium to 140 characters is perfectly complementary to a mobile experience.
The promise of the early web was that everyone could have a website but there was something missing. Maybe the technology wasn't ready.
Just because someone uses Twitter doesn't mean they shouldn't use WordPress, and vice versa.
If you want to be good at something, you really have to work at it every single day. You have to work hard at the things that are hard. Otherwise you are just treading water.
Ultimately, Captchas are useless for spam because they're designed to tell you if someone is 'human' or not, but not whether something is spam or not.
It turns out that social networks drive a heck of a lot of traffic to blogs.