Social bookmarking is already well spamfested. Now they are advocating it
Probably everyone at the plex is very excited about web 2.0 and wants to make google more moment-oriented. Unfortunately, that means a) undue emphasis from a small number of social bookmarking sites b) Social bookmarking sites are really easy to spam, so therefore google is easy to spam c) Social bookmarking sites are clogging up with spam because everyone is using them to rank in google d) this will be the death of social bookmarking.
Google is like King Midas: everything he touched turned to gold. He thought this was great, until he hugged his daughter and turned her into a golden statue. You don't want to be embraced by Google. You want to be invisible to them, lest they apply their golden touch.