Charm publishes a URL psuedo-protocol to invoke the iOS app from other sources.
To invoke the app, use:
x-charm://
To prompt a user to create a new collection:
x-charm://new
To prompt a user to add a Tweet to a collection
x-charm://collect/<tweet-id>
To present a user's timeline for curation
x-charm://user/<screen-name>
To present curation search results for a term
x-charm://search/<term>