While accessibility is often viewed as an afterthought and no more than a legal requirement by web developers, there is a movement to design websites with universality in mind, where those with hearing issues, limited mobility, and visual impairment can have unrestricted access to websites. This trend has emerged while smartphone devices present their own set of challenges with limited screen real estate.
Despite Tim Berners-Lee's utopian vision for the Web, today's Web remains a network of largely inconsistent web pages. Google and other search engines, however, are looking to make sense of the Web with robot scripts that parse the Web, and from this stemmed another industry: search engine optimization.
Prior to Google, legacy search engines relied on good faith of individual webmasters. All insights came from meta tag information, keywords, and hyperlinks present in each page, and many webmasters would masquerade or falsify information to rise in search engine ranking. This has changed, however, with Google and its algorithm to check each website's content relevance and relationship with other websites. Things have become much more complex as search engines now offer personalized search results based on the user's location and prior experience with the Web.
In addition to basic optimization techniques ranging from frequent updates to compressing images, today's webmasters opt to advertise on Google Adwords and monitor on Google Analytics. As the industry leader, Google Analytics allows the users to easily track granular information about visitor activity on the website, including pageviews, visit duration, and traffic sources.
It is important to note that while HTML remains a core component to any website, each HTML web page is designed to be its own entity. Without the help of a programming language, it is impossible to have one HTML page to affect another. This is especially problematic if the website is designed to host a common menu or header bar (imagine building a massive website -- 50 pages or more -- using only HTML).
However, one may use a common CSS file across multiple HTML pages, allowing the developer to easily implement an overarching visual style. A single HTML page can also hold multiple CSS files, which allow for compartmentalization of style.