A good ‘rule of thumb’ would be that the article should be no taller than your browser window before the cut, including the site’s header. (Obviously, different people have different size browser windows, but then, they also have different size thumbs). Following that rule, I would think even a single paragraph after the cut should be justified.
ETA: This comes from the print idiom of “before the fold” and “after the fold”.
Quick related pair of questions:
How long does a post have to be to need a cut?
How long does a post have to be under the cut to justify clicking through?
A good ‘rule of thumb’ would be that the article should be no taller than your browser window before the cut, including the site’s header. (Obviously, different people have different size browser windows, but then, they also have different size thumbs). Following that rule, I would think even a single paragraph after the cut should be justified.
ETA: This comes from the print idiom of “before the fold” and “after the fold”.