It's About Legibility
This article talked about how legibility and readability are two different things and they should not be confused. First, the article mentions that not all typefaces are or should be created to have their prime function be legibility. Generally, whenever a typeface has more spirit, personality, or distinction, it will suffer on legibility. The less personable typefaces have higher legibility.
The article talks about how counters, serifs, and individual letter shapes can affect the legibility. For instance, sans serifs have an easier time being legible. Typefaces with smaller serifs work better. The best types are "transparent types", as they do not get in the way of the communication process because they do not stand out or distract the reader.
The article also mentions that knowing these things and practicing them helps separate typographers and graphic designers from desktop publishers, which I think is a low blow but I agree with the rest of the article. Knowing the above-mentioned points can help a designer to figure out which typeface should be used for a project, as well as help them in creating their own typefaces.
Georgia & Verdana...
This article talks about a time when type was used to be printed out on paper and how it can look awkward when left on the web. These were terrible times for trying to read something online since a lot of it looked awful, especially italics on the Mac. But finally, a dark cloud has been lifted and Microsoft has hired a designer to make types specifically for web. The designer is Matthew Carter and the typefaces are Verdana and Georgia.
Verdana was named for the verdant Seattle area. It has a large x-height so that the characters look larger but it's not too big so the uppercase can be told apart from the lowercase. It also does not look crowded in apps or browsers without adjustable leading. Verdana's letters do not touch and the bold characters never fill in, even in 4 point. The characters 1, I, l, and J are made so that they can never be confused. Verdana can also be used off screen and look beautiful.
Georgia is the screen serif. Carter did the almost impossible and made the characters comfortable on screen and also attractive. Georgia is similar to Times New Roman but the x-height is larger. It's also smaller than Verdana's though so it feels traditional and pleasant on screen.
A lot of web based fonts aim to be as freely downloadable as possible. This article can be helpful to designers because it gives them two really nice fonts to use for web-based stuff and also gives them an idea of what looks good online.
Matthew Carter
Matthew Carter is a type designer and the son of English typographer, Harry Carter. He designed web 1.0 web fonts Georgia and Verdana.
His career went through the transition from physical metal type to digital type. He became a freelancer as well as typographic adviser to Crosfield Electronics. Along with the webfonts, he designed Bell Centennial, Big Caslon, Carter Sans, Miller, and Sophia.
This can be helpful to a designer because it goes to show that the industry is ever-changing and even an old man can learn to design new things with the times.