[whatwg] Link rot is not dangerous

Henri Sivonen hsivonen at iki.fi
Mon May 18 01:34:02 PDT 2009

On May 15, 2009, at 19:20, Manu Sporny wrote:

> There have been a number of people now that have gone to great lengths
> to outline how awful link rot is for CURIEs and the semantic web in
> general. This is a flawed conclusion, based on the assumption that  
> there
> must be a single vocabulary document in existence, for all time, at  
> one
> location.

The "flawed" conclusion flows out of "Follow Your Nose" advocacy, and  
is not flawed if one takes "Follow Your Nose" seriously.

It seems to me that the positions that RDF applications should "Follow  
Their Nose" and that link rot is not dangerous (to RDF) are  
contradictory positions.

That link rot hasn't been a practical problem to the Semantic Web  
community suggests that applications don't really Follow Their Nose in  
practice. Can anyone point me to a deployed end user application that  
uses RDF internally and Follows Its Nose?

(For clarity: I'm not saying that link rot is dangerous to RDF apps.  
I'm saying that taking the position that it is not dangerous  
contradicts Follow Your Nose advocacy. I think "Follow Your Nose" is  
impractical on the Web scale and is alien to naming schemes used in  
technologies that have been successfully deployed on the Web scale  
[e.g. HTML, CSS, JavaScript, DOM and Unicode].)

> - RDFa parsers can be given an override list of legacy vocabularies  
> that
> will be loaded from disk (from a cached copy).

"Cache" means that you can still go find the original and the cache is  
just nearer.

> If a cached copy of the vocabulary cannot be found, it can be re- 
> created from scratch if necessary.

Do any end user applications that use RDF internally provide a UI for  
installing local re-creations?

On May 15, 2009, at 20:25, Shelley Powers wrote:

> Also don't lose sight that this is really no more serious an issue  
> than, say, a company originating "com.sun.*" being purchased by  
> another company, named "com.oracle.*".  And you can't say, "Well  
> that's not the same", because it is.

It's not the same. A Java classloader doesn't "Follow Its Nose". A  
classloader will find classes in my classpath even if there weren't a  
server at sun.com. Likewise, http://sun.com/foo RDF predicates would  
continue to work in applications that don't "Follow Their Nose" even  
if the server at sun.com disappeared.

However, if the com.sun.* classes were renamed to com.oracle.* and the  
com.sun.* copies withdrawn in a new release of a library, other  
classes that have been compiled against com.sun.* classes would cease  
to load. This is analogous to applications programmed to recognize http://web.resource.org/cc/* 
  predicates not recognizing http://creativecommons.org/ns#*  
predicates. (You can't Follow Your Nose from the former to the latter,  

Henri Sivonen
hsivonen at iki.fi

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