Using the free social bookmarking service del.icio.us you can search by tags or search your account. The tags are now visualised by Vox delicii. Michael Migurski analysis the growth and decay of the 'mind-shares' represented by colours. The coloured stripes represent in almost real time the most popular sites by the users.The intro is worth a read for comprehension.You can also navigate via "Gainers", "Losers" and "Top Names". (Unfortunate titles in the ranking universe!) 'Graphing the mindshare of information' is seen to be a bottom-up activity. Here  you can see what delicious users are saying about the tool.

There is more on CollaborativeRank by the University of New South Wales in Sydney. "Del.icio.us users who bookmark helpful/timely URLs (as evidenced by others subsequently bookmarking those URLs) will be rewarded with higher CollaborativeRank, which means that their tagging will have greater influence on this search engine's rankings." There is a list of the 500 active 'Del.icio.us domain experts'. strong current made it to 339 (4.8.) but is down to a slack 16867 today. (Via Micro Persuasion)