The semantics of blank nodes

Hi Everyone,

In examining the RDF Primer's explanation of blank nodes
it shows some triples which use a blank node:

<http://www.example.org/staffid/85740> 
<http://www.example.org/terms/address> 
_:johnaddress .

_:johnaddress 
<http://www.example.org/terms/street> 
"1501 Grant Avenue" .

While I understand the utility of blank nodes in constructing 
graphs (acting like anonymous classes), to me they seem to 
worsen the semantics of the assertions.  For example, the 
above triples in English would be:

The Staff Member with ID 85740 lives at the following 
Address: 1501 Grant Avenue, ... 

The semantics here in terms of Subject, Verb, Object are:

<Staff Member> <livesAt> <Address>.
<Address> <street> "1501 Grant Avenue".

In other words, the example in the primer uses "address" as a 
predicate thus causing the need for a blank node.  Wouldn't it
be better (in terms of semantics) to have the predicate "livesAt" and 
make address its own Subject (which mirrors how you would 
program it in an OOPL).

Does anyone know of cases where blank nodes improve the 
semantics?

Thanks,

 - Mike
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Michael C. Daconta
Director, Web & Technology Services
www.mcbrad.com