Typography is the art and technique of making language visible. Most people don't think twice about typography, yet it's everywhere. Anytime you are reading, someone has carefully chosen the way words appear to the reader. The size, the spacing, the very forms of the letters.
It's obviously not a very cut and dried subject. Certain fonts can elicit feelings or emotions from the majority of readers, certain fonts don't read easily but can sure catch someone's attention.
Almost everyone who owns a computer has a little bit of knowledge about fonts/typography. A font is basically a style of letters and it's spacing. All computers come installed with some fonts that are packaged with the operating system such as Windows or OSX.
It's possible to acquire more fonts, through packages or software bonuses. The point I am leading up to is that, just because you have a font on your computer, doesn't mean any one else will be able to see it. If you were to print it directly from your computer, the paper would be in that font. If you made an image with the font, the type would be in that font.
If you tried to use that font on the web, it wouldn't work. The web is a different animal. Unless the person had the font on their computer, the font would default. Considering the font was chosen for a particular reason, that information the font was trying to convey just disappears.
Enter Google, center stage.
Google does some very interesting work in the world. From driving cars to a shared repository of fonts. Yes, Google has created “Web Fonts” that people can use. For us WordPress folks that aren't afraid to use CSS, it's as simple as installing a plugin and selecting one of the over 500 available Google Fonts.
Now that we have the possibility, let's talk about whether or not you SHOULD.
For years we've had the ability to “define” a font. And like I said, if it was on the computer it would show up. This gave us some limitations, but also gave us a little control over how information displayed. The fast and hard rules were you used a sans serif (without flags) since it was easier to read and “serif” type worked well as a large headline or with printed material. These rules still apply. If you want something that reads well, you stick with the basic sans serifs: Helvetica, Arial. I would really only recommend “fancy” fonts/typography for headlines. And then, I would also say to use them sparingly. For every font you enable through your plugin, there is a “call” to the Google repository. Some people have said that this slows their site down (since this call goes out before the page displays, and the page won't load until it gets the information it asks for.)
When you are thinking about fonts:
Size matters. The large the font, the easier it will be to read, and more likely it is to catch the eye. Unless of course it's all the same size, then obviously, that doesn't work.
Weight Matters. A bold font will draw more attention than a regular weight font. It's thicker and has more “mass” to it. Unless of course all the type on the page is bold.
Italics should be avoided. Italics don't display well at smaller sizes and become hard to read. If you must use italics, use them at larger sizes.
Decorative fonts will all have “emotive” information to them. Scary, cheap, professional, funny, zany, etc. Use these infrequently and never as the “body” or main part of the content. When it's small it will be difficult to read and a lot of it will lose it's impact.
So that it's! Some tips and advice about fonts on your WordPress Site. Just remember the tips above and use your favorite “Google Fonts” plugin. Of course you can also use Google Fonts on regular websites, you just have a few other hoops to jump through.