Google have started a sort of social software version of a search engine. I am not sure it is as networked as the Eurekster Swicki idea. I have tried to start with it and it seems to me intended to have a fairly sharp focus. There is no word cloud for example. These are great to show that there are different aspects to a collection and the relative sizes show how much each is used. I will still work on the Eurekster Swickis and I expect the Google move to strengthen this concept. There is a page showing mine at Learn9.net, Hello Spiders.
The 'learn9' one is important for me as it shows links between quality and learning. I don't find this much in academic sources where learning is studied.
The Google ones are focused just on PDF, ISO 9000, quality and learning. You can put the same query into each if you like. The ISO 9000 one assumes an 'objective' model is possible for any system. The 'quality' one includes 'critique' and all other options. That's the design intention anyway.
And now a graphic for the PDF Search Engine. The Google idea of a graphic is not very flash, but it probably loads fairly quickly.