Text is a UI
It’s a common mistake to think that only full-fledged graphical user interfaces count as interaction design and deserve usability attention. As our earlier research has shown, URLs and email both contribute strongly to the Internet user experience and thus require close attention to usability to enhance the profitability of a company’s Internet efforts.
In fact, the shorter it is, the more important it is to design text for usability.
Some true words in here, even though i think you shouldn’t spend too long thinking about your single tweets. For business okay, it’s important to do so to get the best chance people will see and click, but still… i’d compare it to the subject of a newsletter. People will open it if they are interested and the subject caught their eye. Really important is WHEN you send/tweet it, i think.