Users can construct indexes by creating lists of URLs. Most
client programs allow people to do this easily. Many users then
advertise these hotlists by adding them to their own pages in
their own web servers. Some sites keep hotlists or bookmarks
organised by subject or by research interest. Some sites even
let users submit new entries for their indexes. This allows
navigation (although it doesn't really help searching) in the
Web. Each hotlist or list of bookmarks represents another tour
or view of the places of interest to the author of that hotlist.
As more and more sites and users construct such lists, the
density or value of referenced information increases.