Wednesday the 8th September saw another good turnout for the local meeting for the Web Standards Group - if you are in Brisbane and interested in standards, I can only encourage you to attend. Very educational.
This month John Allsopp of Stylemaster fame flew up to speak. Man, what an empassioned speaker!
We had the expected push for Web Essentials ‘04 - (which looks like it is going to be an excellent conference. The place to be. Wish I could go… :( ) and then John got into his topic for the evening - semantics. A fascinating topic, it brought back so much from my university days. I must have looked like a right twit, nodding to everything he said!
These are my notes. I can’t guarantee that John actually said all of this, its possible I imputed things between what he actually said out loud and wrote it down:
Semantics - what is it? Semantics pertains to what something is, as opposed to Syntax; Semantics defines the What, Syntax the How.
So, the oft mooted Semantic Web is about getting meaning out of HTML (as a generalised reference to (X)HTML)
For example:
When a newpaper italicises something, it can mean several things - it might be a citation, it might a foreign phrase, or one of several other uses. The human brain is able to figure out what the implied usage is through context. However, somputers aren’t that clever; they will not be able to determine what was the meaning of the italicisation.
If, rather than simple italics (in web terms, the i tag), we apply semantic meaning to a phrase, then computers will be able to more accurately determine what we mean.
Syntax is in essence grammar.
The example sentence ‘colorless green dreams sleep furiously’ is a classic example of a perfectly syntactically valid sentence that is semantically meaningless.
Computers are good at extracting info from context, but computers are really, really bad at it.
5, 10 or 15% of visitors may be disabled, but every single pageview is ‘viewed’ by a computer before it is seen by any human, so computers are in fact the most important users of our webpages. So it is primarily important that computers can easily read your page - so it must be semantically meaningful.
The W3C Semantic Extractor is great for evaluating whether a page has semantic meaning or not - we compared The Australian Federal Government Site and Harvey Norman. The difference in semantic meaning between the two sites is stunning.
Sidenote: The Australian Disability Discrimination Act of 1992 states that it is unlawful for a person who provides goods, facilities or services to discriminate on the grounds of disability either on terms and conditions or the manner of provision.
This means that businesses must make their websites accessable, or be at risk of suit. Making a site semantically meaningful is a big step towards accessability.