Youngman and Scharff (1998) show that there is a relationship between text line length and whitespace margins and readability. Readers tended to prefer a text line length of 4 inches.
Bob Bailey from Human Factors International reviews the literature, and suggests that users tend to read faster if line lengths are longer (up to 10 inches). That line lengths of less than 2.5 inches tend to impede rapid reading. And that users prefer lines that are somewhere in between, 4 to 5 inches.
Bob Bailey has also been kind enough to summarize the effect of different layouts on search times, accuracy of finding information and search efficiency (as measured by number of clicks, use of the Back button, etc.). His reviews the research Bernard and Larsen (2001) from Wichita State University. The results indicate there are no significant performance differences between fluid/liquid designs, left justified fixed width designs and centered fixed width designs.
What does it all mean?
There is a relationship between screen resolution and line length. Users can read longer text lines faster. This means that a higher screen resolution can be read faster. This supports the reading speed and monitor resolution seen in my undergraduate thesis from 1996.
But reading speed is not the only consideration when designing a web page. Users tend to prefer more white space and shorter line lengths. If you are designing for satisfaction then content should be designed for approximately 5 inches or 55 characters wide.
Web Site Layout by Bob Bailey
Optimal Line Length by Bob Bailey
What is the Best Layout for Multiple-Column Web Pages? by Michael Bernard & Laurie Larsen
Text width and margin width influences on readability of GUIs by Melissa Youngman & Lauren Scharff
Hypermedia and Reading Comprehension by David Crow
The Effects of Line Length on Children and Adults’ Online Reading Performance by Michael Bernard, Marissa Fernandez & Spring Hull