Washington already allows online voter registration. The Facebook app automatically adds information from a user's Facebook profile. National Journal notes the Washington state app is getting a push from Rock the Vote.
Washington requires its online registrants to have a state-issued identification number for verification. To prevent duplicate registration, the state’s system will reroute a user with an already-registered state ID number to a page that gives information about upcoming elections and allows voters to update their addresses and other information.
The use of information collected by a third party online presented new challenges for the state, in terms of protecting personally identifiable information. Rock the Vote and any other organizations that use a similar interface for online registration will be given the choice to tag registrations with a code that identifies the organization. However, that information, once collected, is public and can be requested by anyone interested in reviewing voter registrations.
It will be made clear to groups funneling potential voters to register with the state that such information will be public, Hamlin said, and it will be up to them whether or not to supply an organizational ID.

