scutters for Topic Maps and RDF (assertion spidering/subject integrating bots): state of the art?

Dear colleagues,

I am looking for the state of the art in Topic Maps and RDF scutters
(assertion spidering bots).

Do you have any useful pointers/hints?

Do you have any information concerning the following four questions:

(1)
Which available collections of statements/assertions do you know and can
you recommend to me for a content aggregation scenario by subject?

(2)
Which scutters (spidering information agents for RDF and/or topic maps
(or fragments) do you know/can you recommend?

(3)
Which sites freely offer semantic web services?

(4)
Do you know of demo sites which can be externally queried with TMRAP 0.2
(or higher: 1.0, 2.0)?

For details with some references see:
http://asigel.blogspot.com/2006/02/topic-maps-and-rdf-scutters-assertion
..html

cu
alex
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Alexander Sigel, M.A., Researcher in Semantic Knowledge Networking
Univ. of Cologne, Dept. of Information Systems & Information Management
http://www.wim.uni-koeln.de/19.0.html
sigel@wim.uni-koeln.de, +49 221 470-5322