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about work done behind the curtains, here another tiny addition to this
site. If you ever looked at the source of this page, you will notice
that as of today there is one line added near the end of the

< link rel="meta"
type="application/rdf+xml" title="FOAF" / >

which will point
spiders and suitable aggregators to the (first installment of) my own
_foaf-file_. According to the Friends of a Friend (FOAF)
its intended purpose is

FOAF is a way to
describe people and relationships to computers. FOAF stands for Friend
Of A Friend. Technically, it is an RDF/XML Semantic Web vocabulary.
Because of this, FOAF data is easy to process and merge.
pages typically say things such as:
“My name
“I work for…”
interested in…”
“I live near…”
“My blog is…”
“I write in this
“You can see me in this
FOAF is a way to say all those things, but
so that computers can interpret it. Computers can’t understand English
yet, so we have to be a little more precise in how we say these things.
FOAF is a way of saying these things for computers.
What would
computers do with this information? We experiment all the time, but here
are some questions that computers can answer using FOAF data:

“Show me pictures of bloggers interested in (foo) who live near
“Show me recent articles written by people at
this meeting.”
“Is this person vegetarian?”
FOAF is a SemanticWeb project. The Semantic Web is an effort to make
it easier for computers to get useful information from the Internet.

Sounds intruiging doesn’t it? But how do they go about
realizing some of this? Well, by encoding all relevant information which
you are willing to share about yourself, people you know, your work etc.
in an RDF (Resource Description
file. The source file can be bit scary at first but
fortunetely you do not have to type these tags yourself. To begin with
your own core-FoaF file, you can use the excellent on-line foaf-a-matic or
the Java-desktop version foaf-a-matic mark
2 beta-2
. Just fill out the data you want to include and these
programs will turn this info into proper FoaF-code. There is one
important thing to consider. These two programs allow you to keep
email-data out of the FoaF-file (for obvious spam-reasons). However, the
whole FoaF-strategy is based on linking various FoaF-files together into
one semantic net and for this reason one has to be able to identify a
person which may occur in different FoaF-files under different nicks or
slightly different names. FoaF takes as its Unique Person Identifier the
email address, so removing this data from your file makes it entirely
useless. Fortunately, the FoaF-community came up with an alternative
keeping the email-address as the UPI but scrambling it to make it
useless to spam-bots. That is the whole purpose of tags such as

 mbox_sha1sum ac5cefa7e1e7df92f7257ea663dfd06a4a4be212

which gives the result of applying the _SHA1_
function to a ‘mailto:’ address. I haven’t checked the online
foaf-a-matic, but the desktop version manages to give the sha1 of your
own email address, but doesn’t give those of the people you know. So, I
had to use the online sha1
and paste the result into the file. Still, all of this
is just scratching the surface. Later on, I will extend my FoaF-file by
adding more people, together with additional information about them and
myself. To get an idea of what information you can encode have a look at
the FOAF Vocabulary
. You can at all times check on the progress looking at
the source file reference. This last bit was achieved by the FoaF header plugin
for WordPress

Published in web


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