Except that "people in Philadelphia suck" isn't a shorter way of saying "some people in Philadelphia suck". It's an entirely different statement.

Why not shorten it to "some Philadelphians suck"? It's shorter and, arguably, more accurate.

>The 140 character limit and general focus on brevity encourages people to drop specificity and shift to bold proclamations and absolutes.

I disagree that the limit encourages vagueness, bold proclamations, and absolutes. Those are side effects of not stopping to think about how to effectively convey a greater-than-140-characters thought in less than 140 characters (without changing its meaning.)