A tracking engine may respond to a first user requesting to pin a link included in a message received from a second user by storing the link in a database table associated with the first user. Alternatively, if the first user requests to clone the link, the tracking engine may store the link in the database table as well as generate a local copy of a file associated with the link. The tracking engine may generate, based on the database table, a user interface for displaying, at a client associated with the first user, one or more links received by the first user. The tracking engine may update the database table to mark or remove invalid links. As such, the user interface that is generated based on the database table may exclude invalid links or include unselectable user interface elements for the invalid links.