Usability, DOCTYPE, XHTML, Boiler... what?

These readings went from good to "meh" pretty quickly.

Usability,  I understand you. Keeping things above the scroll (like above the fold in Journalism), using certain colors, sizing your input boxes correctly and images of people facing the user are definitely tips to refer back to when we are creating our own personal web pages.

From there, for me at least, it went a little downhill.

DOCTYPE is the type/version of html that tells your browser the type of html you're using?

XHTML is Extensible Hypertext Markup Language? And it is almost identical to HTML 4.01? Is a stricter and cleaner version of HTML 4.01? Is just HTML defined as an XML application? Is supported by all major browsers.?

I understand its supported by all major browsers.

I'm still not sure what a boilerplate is.... and I try to get into coding, but all I see is a mess of letters, numbers and symbols. It'll never end. Too bad this post isn't very informative, but I'm just expressing my thoughts about the readings. :/

Honestly, I think I need a nap.