Rob Sanderson wrote:
> info URIs, In My Opinion, are ideally suited for long term identifiers
> of non information resources.  But http URIs are definitely better than
> something which isn't a URI at all.
Through this discussion I am clarifying my thoughts on this too. I feel 
that info URIs are especially suited for identifiers that are not only 
long-term identifiers of non-web resources (an ISBN may identify an 
'information' resource, but it's not a web resource), but also 
especially when in addition all of the following are true:

0) Of potential wide-spread (not just local) interest. Ie, NOT a URI for 
a record in my local catalog.
1) The identifier vocabularly itself pre-dates the web and was not 
designed for the web. (ISBN, SuDoc).
2) There is not a controlling authority for the identifier vocabularly 
that _recognizes_ it's responsibility to maintain persistence _and_ has 
the resources to do fulfill that responsibility. That could be be because:
    a) There is no single controlling authority at all, the control is 
distributed, and they don't all have their coordinated act together for 
a web-world.
    b) The controlling authority hasn't yet realized that these 
identifiers matter for a web world, and don't care about URIs.
    c) There's nobody that wants to commit to this because they think 
they can't afford it.

That's what I'm thinking.  URI for a wikipedia concept from dbpedia?  
Sure, use http.  Those aren't going anywhere, because they are 
web-native, they were created to be web-native, the folks that created 
them realize what this means, and as long as their project exists 
they're likely to maintain them, and they're project isn't likely to go 

URI for an ISBN or SuDocs?  I don't think the GPO is going anywhere, but 
the GPO isn't committing to supporting an http URI scheme, and whoever 
is, who knows if they're going anywhere. That issue is certainly 
mitigated by Ross using for these, instead of his own personal 
http URI. But another issue that makes us want a controlling authority 
is increasing the chances that everyone will use the _same_ URI.  If GPO 
were behind the URIs, those chances would be high. 
Just Ross on his own, the chances go down, later someone else (OCLC, 
GPO, some other guy like Ross) might accidentally create a 'competitor', 
which would be unfortunate. Note this isn't as much of a problem for 
"born web" resources -- nobody's going to accidentally create an 
alternate URI for a dbpedia term, because anybody that knows about 
dbpedia knows that it lives at dbpedia.

So those are my thoughts. Now everyone else can argue bitterly over them 
for a while. :)

And yes, I agree fully that ALL identifiers ought to be expressed as 
_some_ kind of URI.  Once you've done that, you've avoided the most 
important mistake, I think.