# Metadata
## Obiettivi di apprendimento

* Understand that metadata is necessary to communicate the semantics of content
* See that using metadata for ranking in search results is a bad idea
* get introduced to modern ways of publishing media data as RDFa

## Trascrizione

Metadata placed in the head of your HTML page meta tags often have both the name and content attributes
Metadata was foreseen very early as part of HTML, but:
* it does not really work
* usual problem: ignored
* worse problem: intentionally forged, e.g. wrong keywords given in order to mislead search engine
* result: search engines have ignored metadata for two decades
Situation changed with:
* SearchMonkey
* RichSnippets
* Schema.org
Difference:
* People behave
** to maximize their benefit
** targeted benefits:
** Being found and highly ranked by search engines
** Displaying what you want to be displayed
*** Resulting rationale:
**** Incentive mechanisms must make sure that the targeted benefits are achieved
**** Idea for search monkey:
***** don't use metadata to improve finding and ranking by search engines (since it is not readable it incentivizes people to mislead search engines)
***** use metadata to improve the display - namely the display of search engine result summarization
***** Implications:
****** authors care about appropriate presentation
****** incentives for authors/publishers, search engine providers and users who search coincide
Semantic annotations:
* microdata
* microformats
* RDFa
15% of web sites/pages use some form of semantic annotation
Show examples how to do semantic annotation using RDFa (note to Rene. I'd target the philosophy to show students newest developments, such as HTML5; in the same vein: don't show micro format, micro data, but RDFa)

## Quiz

Web Science/Part1: Foundations of the web/Web content/Metadata/quiz

## Discussioni

* Ethernet
** Communication over a shared Medium
** Ethernet header
** Minimum package length vs maximum cable length
** Collision detection
** Summary, further reading, homework
* Internet Protocol
** Motivation for IP
** Classful IPv4 networks
** IP forwarding algorithm
** IP header
** Summary, further reading, homework
* Transmission Control Protocol
** End to end principle and connection oriented communication
** Three way handshake
** Port numbers
** Sliding window and flow control
** Summary, further reading, homework
* Domain Name System
** Tree structure
** Terminology
** Zones
** Review some facts about DNS
** Delegating DNS queries
** DNS address resolution
** Summary, further reading, homework
* Internet vs World Wide Web
** Summary of the internet architecture
** Motivation and requirements for the World Wide Web
** Design principles of the web
** Uniform Resource Identifier
** Summary, further reading, homework
* Hypertext Transfer Protocol
** Making HTTP requests
** A simple web client
** A simple web server
** HTTP header
** Content negotiation
** Summary, further reading, homework
* Web content
** Problem setting for web content formats
** Working with XML
** HTML for web document structures
** Layout elements in HTML
** Motivating separation of content and layout
** Cascading Style Sheets
** Media content
** Metadata
** Summary, further reading, homework
* Dynamic Web Content
** Basics of server side web programming
** Forms and HTTP post request
** Handling a post request in a Java Servlet
** Client side JavaScript
** Ajax and the XMLHttpRequest class
** Summary, further reading, homework