It is likely it will bleed out, but comparing to G+ doesn't work. G+ wasn't successful outside some niche groups which moved elsewhere.
Twitter managed to become a central hub for all of Media. Any celebrity, politician, ... with some announcement? - Put it on Twitter. Any gossip? - it makes its circles on Twitter. And from there wit goes into media (as all media authors are on Twitter) and from media back onto Twitter. Will be interesting to see how that develops, as large parts of media replaced their news gathering with tweetdeck or some other tool on Twitter.
Twitter managed to become a central hub for all of Media. Any celebrity, politician, ... with some announcement? - Put it on Twitter. Any gossip? - it makes its circles on Twitter. And from there wit goes into media (as all media authors are on Twitter) and from media back onto Twitter. Will be interesting to see how that develops, as large parts of media replaced their news gathering with tweetdeck or some other tool on Twitter.