I always submit mine to Twitter as soon as they are published. I use the AddThis extension for both Chrome and Firefox for dang near ALL of my "backlinking" or "promotion." and so sometimes I use the AddThis thing for a second tweet which makes it ...slightly different due to it coming from the AddThis extension.
Heck I never look at twitter otherwise. I just don't like Twitter. I honestly don't much understand what ever attracted folks to that lousy social network to begin with.
Facts of the matter are so far as myself is concerned though, I "tweet" ever single last hub that I read.....unless I just (this is rare) thought it was either totally lousy, or otherwise against the stuff that I believe in.
I learned about the hashtag thing sort of late....and it's surely a valuable thing to know, but seeing as how I just don't like twitter anyway (but do use it as a backlink for me and everyone else that I read) - I don't pursue it.