15. A non-transitory computer storage medium storing instructions that, when executed by one or more computers, cause the one or more computers to perform operations comprising: identifying a user; receiving user input from the identified user through an interface associated with a web browser of a client device, the user input indicating a modification to a set of bookmarks for the identified user; in response to receiving the user input: modifying a set of bookmarks stored for the identified user in a client-side storage of the client device; and synchronizing the modified set of bookmarks with a server-side bookmark storage system configured to synchronize bookmarks for the identified user with one or more other client devices.
15. A non-transitory computer storage medium storing instructions that, when executed by one or more computers, cause the one or more computers to perform operations comprising: identifying a user; receiving user input from the identified user through an interface associated with a web browser of a client device, the user input indicating a modification to a set of bookmarks for the identified user; in response to receiving the user input: modifying a set of bookmarks stored for the identified user in a client-side storage of the client device; and synchronizing the modified set of bookmarks with a server-side bookmark storage system configured to synchronize bookmarks for the identified user with one or more other client devices. 16. The non-transitory computer storage medium of claim 15 , wherein identifying the user comprises authenticating the user.