Today trendalicious stores 24 hours of history (currently around 20,000 URLs and their associated popularity statistics) as persistent objects using Franz' AllegroCache. Accuracy is much improved because a URL's popularity can now be calculated as long as the URL is seen at least twice within 24 hours. Using AllegroCache is incredibly easy; any CLOS object can be made persistent by simply setting its metaclass to 'persistent-class' and specifying which slots are indexed. New and modified instances will be automatically stored when COMMIT is called. RETRIEVE-FROM-INDEX finds existing objects by indexed slot, and DELETE-INSTANCE removes an object from the db. Those three functions are the extent of trendalicious' use of AllegroCache but there is plenty more cool stuff including transactions, Prolog queries, and client/server mode.