Markup gives structure to information
I have been missing a lot of things on the Web the past few weeks. I just found Steve Champeon's article on the importance of understanding mark-up over at Web Monkey. HTML markup, some call it HTML code (not correct), helps structure information so that it can be used and reused properly in the proper context. This is extremely important when you are trying to add style to the content, such as adding the desired size and weight to a header or modify positioning to an unordered list. I see a lot of HTML tags that are not used properly in the work we clean-up on a regular basis. There are very few applications, like MS Word that come close to using HTML markup properly. Cleaning up application generated markup is demoralizing as getting markup right in the first place is easier than having to clean up the mess made. Go read Steve's article and anything else you can put your hands on that he has written and you will be much better off than before, believe me.
Why is markup important? Many folks and applications try styling the information without considering the structure of the information. If you have much of a background in communication, journalism, information science, etc. you understand that information needs structure. There are headers that indicate to the user what the content and tone of the content that follows will contain. There are many elements on a page that need structure, like knowing where a paragraph begins and ends, where in the body of text an image should be tied, words that need to stand out (strong), a string of items in a list, or a structured ordered list with sub-elements. Not having thes information properly marked up would make understanding how to best treat that information very difficult. This may seem irrelevant to those that only deal with a Web browser, but if you want to read the informaiton on a PDA, print the information and use the best styling for reading, or need a screen reader to vocalize the words on the page and give the words that compise the information being communicated the same understanding you need structured information. It would be like trying to bake a cake with out sides on the pan, the cake needs structure to rise and be best consumed. People that guide you away from properly strucutring information, more often than not are not informed on the need and the benefits to structuring information.