Creating a Blog from Scratch, Part 5: What is XHTML, and Why Should I Care?

In prior posts in this series (1, 2, 3, and 4), I described with some glee my rash abandonment of common blogging software in favor of writing my own. For my purposes there seemed to be some key disadvantages[1] to these popular packages, including an overemphasis on the calendar (I just saw the definition of a blog at the South by Southwest Interactive Festival—”a page with dated entries”—which, to paraphrase Woody Allen, is like calling War and Peace “a book about Russia”), a sameness to their designs, and comments that are rarely helpful and often filled with spam. But one of the greatest advantages of recent blog software packages is that they generally write standards-compliant code. More specifically, blog software like WordPress automatically produces XHTML. Some of you might be asking, what is XHTML, and who cares? And why would I want to spend a great deal of effort ensuring that this blog complied strictly with this language?