If you find this text hard to read, go ahead and experiment with various settings. Some people prefer larger characters, others like them bold; some prefer a "sans serif" font, others like the aspect of traditional print; many find light text on a dark background (e.g. white on black, or yellow on dark blue) more comfortable to their eyes. Just find out whatever works best for you.
We believe that the author of a Web page should concentrate on contents, not presentation. Computer displays exhibit such a variety of characteristics (size, colors, resolution...) that a page "optimized" for a particular display or browser is bound to look ugly and/or difficult to read on another one. This is why we leave as much freedom as possible for the reader to adjust to his/her particular circumstances. In particular, we avoid frames, sensitive maps, and other features that do not readily scale to fit various environments.
These portability and accessibility guidelines are important everywhere, but even more on a site of interest to visually impaired people, many of whom use screen magnification software, text-only browsers, speech synthesizers or braille displays.
Web designers who wish to make their sites accessible and comfortable to a large audience (don't they all?) may be interested in the following sites: