U.S. - According to a new report, the nation's grandmothers are still unclear on the difference between a public Facebook comment and a private message.

The federal government researched the phenomenon and confirmed that 97% of grandmas still aren't sure what the difference is.

"Our study confirms that grandmothers still believe there is no difference between sending you a private message and just vomiting a bunch of thoughts into the comment section of your vacation photos or pics of your home remodel," Dr. Billy Swain, head researcher on the official U.S. government study, said. "They are relentless. As soon as you post something, they are compelled to post a lengthy public comment asking you how the grandkids are doing or telling you about their most recent Bridge tournament."

Common topics grandmothers like to bring up on completely unrelated posts include gout, the weather, baking, Matlock, President Obama, and social security. According to the study, there is "little to no" correlation between the Facebook post they are commenting on and the content of their comment.

"In only rare circumstances did grandmothers post something that's on topic," Dr. Swain said. He did say there was one thing grandmothers immediately zero in on and are able to post relevant comments on: pictures of their grandkids. "As soon as they see those, they are locked in for a few minutes before getting off topic again."