"We will never have LCD screens - they will need too many connectors"
"Vector graphics are the future; raster graphics need too much memory"
"Full audio on computers will need too much bandwidth"
"Digital photography will never replace film"
"Moore's Law hasn't got much longer to go" (1977, 1985, 1995, 2005)
We all know this one. But often people don't understand its true effects.
Take a piece of paper, divide it in two, and write this year's date in one half:
Now divide the other half in two vertically, and write the date 18 months ago in one half:
Now divide the remaining space in half, and write the date 18 months earlier (or in other words 3 years ago) in one half:
Repeat until your pen is thicker than the space you have to divide in two:
This demonstrates that your current computer is more powerful than all other computers you have had put together (and the original Macintosh (1984) had tiny amounts of computing power available.)
In the 1980's the most powerful machines were Crays
And people used to say "One day we will all have a Cray on our desks!"
Sure: in fact current workstations are about 120 Craysworth.
Even my previous mobile phone was 35 Craysworth...
What is less well-known is that bandwidth is also growing exponentially at constant cost, but the doubling time is 1 year!
(Actually 10½ months according recently to an executive of one of the larger suppliers)
Put another way, in 7 years we could have 1 Gigabit connections to the home.
Elevator pitch: Like CSS, which adds a layer of markup to influence presentation, RDFa adds a small layer of markup that adds semantics to documents.
Now a browser can know more about the page you are looking at.
If you are looking at a page about an event, the browser could offer to
etc.
RDFa can also help search engines, and even allow the creation of new sorts of 'aggregators'.
The 'a' stands for attributes, since RDFa uses attributes to signal data.
<p typeof="service:restaurant"> <strong property="service:name">Rose's Cantina</strong> <span property="address:street">Regulierdwarsstr 38</span> <a property="address:phone" href="tel:+31206259797">6259797</a> ... </p>
(The ontologies used here are made up, for the sake of simplicity)
<span property="restaurant:cuisine"
content="cookery:mexican">Mexican</span>
Language independent
Allows cuisines to have properties as well.
<p about="cookery:mexican">As the name suggests, Mexican cuisine originates from <span property="ont:origin">Mexico</a> </p>
Beginning to be widely used: BBC, Governments, Google, Yahoo, Tesco, Best Buy, New York Times:
"GoodRelations + RDFa improved the rank of the respective pages in Google tremendously …
30% (!) increase in traffic …
Yahoo observes a 15% increase in the Click-through-Rate …”
Clearly, if the browser knows more about the page, it gives great possibilities for accessibility.