An identity is an alternate "From" for your post so instead of coming from an individual (you) it can come from your department, center, club, etc. A small image can be added to the identity. Identities are strictly controlled under the rights management in Timeline so that only authorized persons have the ability to post under a specific identity. The identity owner can add additional admins to also be able to post as the identity.
If you would like to set up an identity for your group, please contact the Timeline administrator.