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Size of the Semantic Web was: Semantic Web Ontology Map

From: Chris Bizer <chris@bizer.de>
Date: Sat, 28 Jul 2007 11:15:45 +0200
Message-ID: <002601c7d0f7$e12e0ea0$c4e84d57@named4gc1asnuj>
To: <gv@btucson.com>, "Kinsella, Sheila" <sheila.kinsella@deri.org>, "tim finin" <finin@cs.umbc.edu>, <lushan1@umbc.edu>
Cc: <semantic-web@w3.org>

Hi Sheila and all,

it is a great idea to try to draw a map of the Semantic Web and to provide 
people with a place to refer to in order to see the Semantic Web grow.
So great idea!

But what confuses me a bit is your claim that this is a map of THE Semantic 
Web as June 2007.

You have got 200 000 RDF files.

If you look at Swoogle's statistic page 
http://swoogle.umbc.edu/index.php?option=com_swoogle_stats&Itemid=8, you see 
that they have 1.2 million files amounting to 436 million triples.

If you look at the Linking Open Data project page 
you will see that there are over one billion triples and I would guess that 
the different servers within the project serve around 30 million RDF 
documents to the Web.

So my guess would be that:

- your dataset covers less than 1% of the Semantic Web
- Swoogle covers about 4 % of the Semantic Web

as of June 2007.

So I think it would be important that people who claim to cover the whole 
Semantic Web would give some details about the crawling algorithms they use 
to get their datasets so that it is possible to judge the accuracy of their 

The datasources in the Linking Open Data project are all interlinked with 
RDF links. So it is possible to crawl all 30 million documents by following 
these links. Good starting points for a crawl are URIs identifying concepts 
from different domains within DBpedia, as they are interlinked with many 
other data sets.

Some background information about the idea of RDF Links and how crawlers can 
follow these links are found in



Chris Bizer
Freie Universitšt Berlin
+49 30 838 54057
----- Original Message ----- 
From: "Golda Velez" <w3@webglimpse.org>
To: "Kinsella, Sheila" <sheila.kinsella@deri.org>
Cc: <semantic-web@w3.org>
Sent: Saturday, July 28, 2007 5:31 AM
Subject: Re: Semantic Web Ontology Map

Very cool!  Is there also a text representation of this graph available?



> Dear all,
> For those of you who are interested in seeing what type of RDF data is
> available on the web as of now, we provide a current overview on the
> state of the Semantic Web at http://sw.deri.org/2007/06/ontologymap/
> Here you can see a graphical representation which Andreas Harth and I
> have created showing the most commonly occurring classes and the
> frequency of links between them.
> Any feedback or questions are welcome.
> Sheila
Received on Saturday, 28 July 2007 09:16:29 UTC

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