1. A method for adapting entity mentions in a feed item to requirements for posting on multiple online social environments, the method including: receiving a request to post a feed item on multiple online social environments, wherein the request mentions at least one identifier that identifies an entity; receiving a selection of the multiple online social environments for posting the feed item; matching the identifier to a particular contact stored in a database, wherein the contact holds supplemental information that includes multiple social handles of the entity for at least some of the multiple online social environments; retrieving the multiple social handles associated with the entity; creating different instances of the feed item, wherein the different instances include social handles that are specific to the multiple online environments; and embedding the different instances of the feed item in the online social environments.