To send a message to twitter or any other network you have to click on
one of the symbols below. They are at the bottom of your blog post
after you click send. You need to click on the relevant icon. If you
stay signed in with your networks it will automatically take your post
to twitter or whichever network you want to use.
See the social network icons here:

Once
you click the icon you will be taken to your network and probably asked
to submit your blog...