Thanks, but I'm not interested in "pushing" anything, really (I call that spam). I'm just trying to position Twitter where it belongs amongst the "link sharing

Thanks, but I'm not interested in "pushing" anything, really (I call that spam). I'm just trying to position Twitter where it belongs amongst the "link sharing" websites (yes, you're right, I should also take StumbleUpon into consideration): how big is it really, how over-hyped, how over-valued etc.