(Apologies to people on mobile for the following...)

  One of the things I miss about Usenet was that
  nearly everyone read it with a fixed with font
  so that if you choose your phrasing well so as
  to make your text come out naturally perfectly
  justified, it would come out that way for them
  too.

  English has so many synonyms and near-synonyms
  for every word, and so much flexibility in the
  ordering of words that you can write like this
  in near real time.

  You get to the end of a line, find that you're
  just a little long or short, and you backtrack
  just a couple words or so most of the time and
  you can usually find a way that works. In this
  paragraph, for instance, I was one too long in
  the first line, but contracting "you are" down
  to "you're" fixed it. I was short in that last
  sentence, but inserting "down" fixed it.

  Perfect justification by inserting extra space
  is for amateurs.

  Now we've got all fancy and use variable width
  fonts and automatic wrapping and posting isn't
  quite as fun anymore.

  Give it a try. Use an editor with a fixed font
  to compose your next post and try to get it to
  come out perfectly justified without having to
  insert extra spaces. When you paste it into HN
  that will get lost, but the composing can be a
  fun little English puzzle.

I read at one point that the typesetters at the New Yorker would work with the copy editors to fix cases of bad justification (huge word space, awkward hyphen). It's rare to see that kind of care, but automatic algorithms are getting better.

On topic to the original post, I implemented Knuth-style line breaking in the Android text stack (working with Anish Athalye who was an intern at the time and did the first prototype). There were a bunch of nicely tuned implementations of advanced data structures and algorithms in there.

s /a fixed with font/fixed width fonts/ in the second line