15. A computer program product comprising: a computer-usable medium having computer-usable program code that manages online communities, said computer program product including: computer-usable program code that declaratively specifies a taxonomy of online community types; computer-usable program code that declaratively specifies a plurality of roles for members of online communities; computer-usable program code that declaratively specifies a security policy that associates permissions with roles and online community types; computer-usable program code that maintains a plurality of online community profiles, wherein each online community profile represents an online community, specifies an online community type from the taxonomy, and specifies a list of members of the online community and an associated role for each member; and computer-usable program code that provides access to a selected online community according to the online community type of the selected online community, a role within the selected online community associated with a user attempting to access the selected online community, and the security policy.
15. A computer program product comprising: a computer-usable medium having computer-usable program code that manages online communities, said computer program product including: computer-usable program code that declaratively specifies a taxonomy of online community types; computer-usable program code that declaratively specifies a plurality of roles for members of online communities; computer-usable program code that declaratively specifies a security policy that associates permissions with roles and online community types; computer-usable program code that maintains a plurality of online community profiles, wherein each online community profile represents an online community, specifies an online community type from the taxonomy, and specifies a list of members of the online community and an associated role for each member; and computer-usable program code that provides access to a selected online community according to the online community type of the selected online community, a role within the selected online community associated with a user attempting to access the selected online community, and the security policy. 18. The computer program product of claim 15 , further comprising computer-usable program code that associates a resource that is external to the online community management system with an online community.