The first part of this article first distinguishes "restricted knowledge representation (KR) and sharing (KS)" and the still seldom researched task of "general KR and KS". This parts then highlights the usefulness of the latter for disaster management, and provides a panorama of complementary techniques supporting it. The research question that these techniques collectively answer is: how to let Web users collaboratively build KBs (KR bases) i) that are not implicitly "partially redundant or inconsistent" internally or with each other, ii) that are complete with respect to certain criteria or subjects, iii) without restricting what the users can enter nor forcing them to agree on terminology or beliefs, and iv) without requiring people to duplicate knowledge in various KBs, or manually search knowledge in various KBs and aggregate knowledge from various KBs? In a second part, this article shows the way various kinds of disaster management related information can be categorized or represented for general KS purposes, e.g. terminologies and information objects (these objects are rarely represented via KRs; examples about Search & Rescue procedures are given).