This is a strategy for coming up with the right size of a contribution to some kind of online system. Figure out what the size of the input box is, and then fill it up with what you have to say so that everything you type fits without scrolling.
If your email client gives you ten lines to type your message, type ten (and not two or twenty). If letters to the editor have to be less than 500 words, never make it 600. If you crummy old cell phone has a tiny screen, learn to abbrev your memos to self.
This principle works as well for paper input methods. I am a recent convert from quadrille ruled 8.5x11" lab notebooks to a quad ruled pocket Moleskine notebook; it's so much easier to fill up a page with one thought when the page only fits five long sentences vs. five long paragraphs.
It turns out that on my browser in this workspace that the input box has room for roughly four short paragraphs. That's about right. The comment box has room for a two or three line note; that's also almost right.
The input box for the Vacuum wiki where I first wrote "Fill the input box without scrolling" is somewhat smaller than the Ecto input box, so I'm writing a little more - but not much. It's a cheat to change fonts or page widths from the defaults, but I did slide the slider between first-page and following page for this one.