Commercial SW enabled portals

I would be grateful if anyone could point me in the direction of any
commercial SW enabled portals which facilitate procuremnt.  I'm thinking of
something like an intelligent Kelkoo (www.kelkoo.com) which is used for B2B
rather than B2C, where businesses can browse and compare company products in
closely related categories (e.g. foodstuffs or building materials).  I've
come across some activity using SW in portals but these appear to be more
community oriented, might there be reasons for this - or might businesses
just not want their products compared closely with their competitors?!

Any recommendations or comments would be much appreciated.
Ivor