OAI-PMP and COINS are ways of distributing your collection metadata.

COinS (ContextObjects in Spans) is a simple, ad hoc community specification for publishing OpenURL references in HTML.  Or more simply  a convention to embed bibliographic metadata in a line of HTML code.

 ResCarta Web reads the metadata content of your MODS metadata and embeds it in an in-line HTML code string.  This can be read by harvesters like ZOTERO and others.