While there's no problem with the numerous photos of "I voted" stickers that have been floating around the Internet today, snapping and sharing a photo of a ballot, as many people did, is illegal in many states.
Technology website Gizmodo.com compiled a list of states and laws answering the question: Is it illegal to Instagram your ballot?
Laws vary from state to state, with some states like Rhode Island having no restrictions on photography in polling places while other states like Missouri expressly forbid revealing a ballot "with the intent of letting it be known how anyone is about to vote or has voted."
In other states such as South Dakota and Tennessee, the law is not clear.
The Citizen Media Law Project also compiled similar information for their Documenting the Vote 2012 coverage.