Lots of bloggers talk about things being “below the break” which appears to be a reference to the fold in newspapers, which puts the headlines and beginnings of stories on the first page, visible on top of a pile of papers or in a vending machine, but the continuation of the story on the lower half of the page, hidden from the casual viewer (generally requiring purchase to see).
This concept makes no sense on a blog, as each viewer may have a different size screen and see different amounts of the beginning material of the blog. Those who read through an RSS feed may see a completely different view than those who read the blog directly.
A similar problem is seen in many web page designs, which seem to assume that all readers have the same screen size, the same fonts, and the same browser. I prefer a lot of the older, simpler web pages, which left most of the formatting to the browser, rather than trying to micromanage the appearance. My eyes are not as good as they once were, and I sometimes like to increase the font size by a couple of points for readability, or force black on white for legibility. Many web pages have such complicated fragile formatting that they break if you attempt to make them readable in these ways.
As you may have noticed, the blog format I’m using is “Rubric” by Hadley Wickham, which is a flexible-width format, so that readers can view the blog at whatever screen size they choose, and can (if their eyes are old like mine) increase the font size for comfort without messing up the blog.
Although I like Rubric well enough, it was about the only choice that WordPress.com offered with both flexible width and a custom header picture. I might have preferred a larger header picture, but all the wide-header formats wordpress offered were fixed-width. (I understand that they have added one or two flexible-width themes in the past couple of months, but none were as clean and text-centered as Rubric, so did not tempt me.)