The way I see it in traditional computer science programming is basically about 1. data and 2 manipulating this data with methods or functions. Now when we look at something like Ruby or Java its clear to distinguish data and method, we have Object which are made up of data and methods, further down we have database, easy!
So why does this matter so much, especially when it come to data. I have taken a closer look at HTML5 new tags and learnt that they are the core of what we are calling now the semantic web or the web that has meaning! Tags such as nav, aside, article and section all have there place in correct structuring of HTML, making it better organised, readable and structured. And structuring data is paramount to any software professional, you would never accept a relational database being unstructured without proper relationships and we all know the headache involved in JSON data not being structured properly. The same way our DOM needs to have clearly structured using semantics. If it is, it mean search engines can query the data providing better more meaningful results to customers, our JQuery would read a better and would be easier to code because similar pattern would be used to create content, it could even mean applications could perform task simply based on the DOM structure, like find how many tickets left for a concert or the amount of time before something finishes (<time> tag). And with the Polymer on the horizon and customer directives already widely used in AngularJS there’s more scope to make sense of the DOM!
All round I see the DOM becoming a massive database of, hopefully, meaningful information that could open up all sorts of doors for now enterprise and idea’s!