Looking for a small knowledge management tool

This is for a small team. Here are some basic requirements :

> storage of links with archiving of the linked page > storage of files (PDF, DOC, ODT, TXT, jpeg, ...) > free tagging of documents > categories > advanced search tool > comments and notes taking associated to each document > multi-user with sharing > integrated into firefox (single click to archive a web page) > integrated into destop computer (right click to add a document) > web site for access everywhere > mobile applications for integration into mobile devices with offline mode > can manage and share a "to be read" list of document > notifications when metadata of a document are modified

Any hint ?

Many thanks by advance. G.