Most people go to a web page because they are interested in the information that is there, either an article they want to read about something or maybe it's a product or service site that requires them to navigate through a number of pages to find the product or service that they are looking for.
The last thing they want to do is have to battle with the font on the page because it is difficult to read.
There are several things that make fonts easy or hard to read and each one is equally as important.
Fonts are made up of many properties but the most important of these are type, size and color.
The type of font refers to how the font characters themselves are displayed. The most common fonts are Times New Roman and Ariel because they are the most easy to read. The reason they are the most easy to read is because they are plain and simple.
There is nothing fancy about them as opposed to a font like, say, Potter, which is an excellent representation of the fonts used in the Harry Potter movie series. They may look real cool but they are not easy to read.
Maybe for a word or two, no problem. But a whole page of Harry Potter fonts could become a reading nightmare for a visitor to your site.
Now, suppose your site was about Harry Potter. In that case it would be okay to maybe have some words using that font, such as maybe headings and the first word of each paragraph. But the majority of your text you would still need to be in easy to read font.
This way you capture the flavor of the Harry Potter world and still give your readers an easy to read experience.
Size is another issue about fonts. Not everybody has 20-20 vision. You don't want the fonts on your page to be too small. If they are, some people are going to have a difficult time reading the material on the page.
A good size for a paragraph font is about 12 to 14 point. Headings can be a little bigger, maybe between 16 and 20 point. By keeping the size of your font within normal parameters you give your visitors the best chance of an easy read of your page.
