Filtering versus discovering annotations

[jbhoward-dublin]

Regarding the filtering functions for annotations--much welcomed. Ideally the list of categories would represent only those motivations that are potentially available. This could be determined, for example, through some local configuration parameter, or possibly from parsing the known annotations for 'motivation' or 'purpose.'

Annotations for an object might exist in more than one location, i.e., more than one annostore; individual locations might support different sets of motivations; and they might also provide their own associated IIIF content search endpoints (and such an endpoint might be different from that identified in the manifest currently being viewed).

Should functionality for annotations include a notifications mechanism for querying a notifications service (or services) for third-party annotations? If a third party's annotations are identified this way, and are searchable via a IIIF content search endpoint, should the location of that endpoint be returned by the notifications service? How, then would M3 negotiate searches when more than one search endpoint is pertinent?