In the process of writing a term paper for a class, I've been paging through many research papers.

Unfortunately, many of these research papers are only available for reading via PDF. Even for those papers that have full text on a normal webpage, complex login and authentication systems (i.e. I can only access said page through my university library) force me to save PDFs to facilitate later reading.

PDFs are really miserable for reading on the computer. My gripes:

Fixed font styles

Many PDFs use serif fonts, which are generally difficult to read on screen (though fine on print media). Some irate designers even create PDFs that use "Times New Roman," which despite it being default on many web browsers is ugly and difficult to read. In a web browser, you can change it; in a PDF, you are forced to suffer with it.

Fixed font sizes

Font sizes are fixed in PDFs, you cannot change them. Often when reading on screen, fonts are just too large, or are too small. This is compounded with...

No wrapping

Text is statically laid out, so you are completely reliant and sizing your window and adjusting your zoom to be able to read a block a text, or stuck with moving your scrollback back and forth.

Columns

Computers have scrollbars. Columns make absolutely no sense when you can scroll. The worst case comes up when you combine columns AND scrolling: you have to scroll down to finish reading a column, and then scroll back up to begin reading the top of the next column.

Usability expert Jakob Nielson thinks so too: in 2003 he had a column PDF: Unfit for Human Consumption.

It seems that some of these problems stem from a mismatch in orientation. Computer monitors are generally landscape; PDFs and printed media are portrait.

And computer monitors just keep getting wider. While widescreen is nothing short of awesome for movies and television, its not that useful for computing. The classic use case is the accountant with a wide spreadsheet: but how many people have wide spreadsheets? Because most people use computers to create content in a portrait orientation, and that most content we read expands downward rather than to the side, it seems as if it would make sense if monitors were a portrait orientation rather than landscape.

Fortunately, this is easy to try out now. Most LCD monitors swivel into portrait orientation with a flick of the wrist. Microsoft Windows and Linux (through the XRandR extensions) have provided orientation switching support for a few years as well.

But it's not yet usable by the mainstream. For example, on Linux with nVidia's binary drivers, running in portrait means losing out on accelerated 3D as well as multimonitor support, things many people (including myself) are not ready to lose.