Jeff tagged this bug as status-completed, and said:
because we loop through comments on the fly for rendering anyway, we are now force-inserting a soft hyphen boring unicode spaces every so many characters without a space. So this should be truly fixed now.
But it doesn't look that way from here:
(Chrome 18/IE8/FF 9 on Windows 7)
To reproduce this, you need a comment with a large number of apostrophes. If you insist on trying it out, you'll of course use the Sandbox for that.
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