del.icio.us has been fixed to remember the actual posting date of an item, so the Be The Coolest bookmarklet won't work any more (the system still lets you set a posting date for an item so that it shows up in the right order in your store, but the list of users who bookmarked an item is in the real posting order, as it should be). Now you can actually use these lists to work out who spots the most interesting items first.
For example this table, the result of reading the del.icio.us popular page and calculating who posted the most interesting items earliest: