I follow people on Twitter because they post on Twitter. If they'd post somewhere else, I'd probably follow them there (within some limits). That doesn't mean I post updates about my stuff there - if others want to follow my updates, they can go where those are.
Arguments used to justify twitter always rely on certain users of the platform. I am not sure how that makes twitter good as a platform. By staying on the platform, you are forcing other developers and people to use it to announce their projects and keep you up-to-date aka networks effect.