When entering data in government electronic forms, there is a significant amount of redundancy. Even if you could save people time/effort in filling out common form elements (such as name, address, birth date, social security number), it would be a huge benefit. Consider a central repository for personal information - totally opt-in and secure - where citizens could choose to log into and use in government electronic forms. For example, if this existed, when a citizen starts the submission process for federal student aid, all the information that she submitted with her federal tax forms would automatically fill-in (instead of having to manually look that information up and enter it by hand).
Sharing of this information to other government agencies should be totally up to the citizen. For example, when applying for Veteran's Benefits, the online form would prompt the user with the information that it could retrieve from the central repository. If the user rejected the retrieval, he would need to enter that information by hand. If accepted, the user would only have to enter information that isn't contained within the central repository. You could even provide the user with the ability to reject retrieval for specific form elements. Once the form is completed, the user is prompted to save updated or new form elements into the repository.
Citizens would have total control over and transparency into their information repository, including which applications/forms have retrieved/stored information and the date/time of the retrieval/storage down to the form element level.
This would require a standardization of form elements (e.g., address = street address separate from city, state, and zip code). Once it is widely adopted by the federal government, it could be adopted by state governments as well (e.g., applying for a driver's license).