I get a little grossed out when too much grammar is either sacrificed or just plain overlooked in those 140 characters.
if you can't fit "you're," please don't substitute it with "your." I'd much prefer to see U R, because that at least proves you've got a grasp of WFT you're saying to the world.
if you can't fit "you're," please don't substitute it with "your." I'd much prefer to see U R, because that at least proves you've got a grasp of WFT you're saying to the world.