1. A system comprising: a processor; a computer-readable storage medium having stored therein processor-executable instructions for causing the processor to: receive, from a client device, a plurality of content items uploaded to a synced online content management system, the plurality of content items being associated with a first user account; automatically cluster at least some of the plurality of content items, having a common attribute, as an event, to yield an event content collection; exclude a subset of the plurality of content items from the event content collection based on input received at the first user account; automatically reassign the excluded subset of the plurality of content items to a new cluster having a second common attribute; generate a suggestion to the first user account to share the event content collection with a second user account that satisfies a minimum similarity threshold for the event based on the common attribute of the event; and make the event content collection available to the second user account when the first user account accepts the suggestion.