RSS Basics - Information Trapping: Real-Time Research on the Web - page 9

where it pretty much ends. here is no way to delineate speciic information
within the content of the page. Take, for example, an HTML page of infor-
mation about birds. While someone might easily be able to scan the page for
information about bird migration, a search engine could not. hat's because
the page simply is not formatted in a way for search engines to look at it and
determine what part of the content is migration information.
You might do a keyword search for words relevant to migration, but the
search engine inding your results might ind the keywords anywhere—in
the header of a page, in menus, or even in the copyright statement! here's
no way that the search can be restricted to the area of the HTML page con-
cerned with migration. HTML pages simply aren't structured to allow a
search engine to break down the information they hold.
XML takes care of this problem by allowing for additional ways to delineate
the information contained in the pages. With XML, you can have a format-
ting style for a page to display information about birds, so both people and
search engines can read it. Why is this important? Because a computer can
read not only this particular page about birds, but also ten million other pages
about birds formatted in XML. hen from this gathered information, it can
build a useful, searchable, outlined chunk of information about birds.
To take this scenario one step further, imagine that a search engine
indexed 10,000 pages about birds from several diferent sites that were
formatted in XML. Because of the XML format, you could search for all
birds that migrated in November, or all birds that eat seeds. With HTML,
you'd have to do keyword searches using words like migration November
cardinal and you'd just have to hope you get useful results.
rSS feeds: a type of XML
So how does RSS relate to XML?
RSS is a type of text ile, a particular type of XML for page and story sum-
maries that is formatted so that the data is delineated very clearly, and bro-
ken down far more than it would be on a regular HTML page. here are
more extensive types of RSS that carry all kinds of data, including sound
and video iles, but this topic focuses on basic RSS text iles. (Once you
begin to trap multimedia, you'll notice plenty of examples of RSS feeds that
carry data in addition to text.)