Usability!...And DOCTYPES?

After reading these four articles, I've come to a realization: I'm still not exactly clear on what a DOCTYPE is. I understand that there are different forms, and they determine how strict to a standard the design must be in order to appear in the way that you intend on certain browsers. Basically, I'm getting the sense that it determines how a site will actually look through different browsers. I hadn't realized that different browsers viewed sites that much differently, but apparently I was very wrong! One thing that jumped out at me was how easy it seems to be to switch to an HTML5 DOCTYPE. However, what's so different about HTML as compared with the various forms of HTML4.01?

The reading on usability was really interesting in my opinion. In one of my past posts I was questioning how much design and layout mattered to a user, and I guess this answers my questions. It was fascinating that such slight differences in white space, search bar width, etc. have a real and measurable impact on the user. These tips are certainly things to keep in mind while designing so that users actually are able to (and want) to view all of the content on our sites. The eye-tracking comparison was very cool as well. I didn't realize that having an image of a face looking at something would drastically change where users look on a screen. Another thing that resonated with me was judging legitimacy on design quality. Thinking about it, I definitely do this when I'm looking at webpages. The design choices we make really send messages to the user, and it's important to be aware not only of what we intend to say, but also the more subtle messages that our designs are sending.