In reply to Arabella Santiago.

Thanks for your comment, Arabella. Guillaume's presentation is quite clear & informative. While I would not call Scoop.it a personal knowledge manager, as only people can do that, I can see how it could be used to support PKM. My personal issue with Scoop.it is the way most people seem to use it; for collection but not curation. Many of my posts get picked up on Scoop.it but only a very small percentage of users add any value. Most "scoops" (is that what they are called?) that I see have no comments added. One exception to this pattern is my friend Robin Good, who understands curation very well: http://www.scoop.it/u/RobinGood

When I advise people on starting a PKM process I suggest they use a variety of filters, as explained here: http://jarche.com/2011/10/knowledge-filters/
Algorithms have a role, though, as Guillaume points out, it is a limited one.