When U.S. citizens or lawful permanent residents sponsor their foreign national husbands or wives for U.S. lawful permanent residence (a green card) based on that marriage, one of the most important things they will have to proved is that it's a valid, bona fide marriage (as opposed to a fraud to get a green card).
In the past, U.S. Citizenship and Immigration Services (USCIS) and the Department of Homeland Security (DHS) would rely mostly on documents submitted by the applicants, the answers to probing questions asked during personal interviews at a USCIS office or overseas consulate, and in rare cases, visits to the home or more extensive investigation to find out whether the marriage was the real things. But as we'll discuss in this article, the prevalence of social media, and its users' tendencies to reveal multiple aspects of their private lives has given the U.S. government a new discovery tool; one that it's making extensive use of.
It's likely that DHS or USCIS will check out your social media accounts. In 2020, it issued a "Privacy Impact Assessment" discussing this very plan, and indicating that it would collect individual information on social media accounts on various application forms. (To date, however, it has not introduced relevant questions into any of the major immigration application forms.) It has also explained that it can create accounts in order to "view publicly available information." Don't expect them to accept invitations to connect, however!
Although official DHS statements say they won't push past privacy settings, comments made by U.S. immigration officials, for example to immigration lawyers at conferences and meetings, suggest that applicants' privacy settings are not a bar to government monitoring. If they want to, they will find a way to look at whatever you've posted on social networks. At times, they simply ask applicants for their social network handles and even passwords to their devices (for example, during a U.S. border inspection).
After poking through people's social network pages, for example, DHS officials report that they've found instances in which the applicant for a marriage-based green card state on Facebook that their marital status is "single," a fact that definitely weighs against the applicant.
Other ways in which an applicant could raise doubts or concerns in the mind of immigration officials are endless: posting lots of photos of fun times with friends but not with one's U.S. citizen spouse, bragging about having engaged in criminal activity (don't laugh, criminals have been arrested based on such disclosures), mentioning illegal use of drugs (a ground of inadmissibility), failing to say a thing about one's wedding despite having posted about every other major and minor incident in one's life for the past year, and so on.
If you are concerned that you'll have difficulty proving the bona fides of your binational marriage to U.S. immigration authorities, by all means consult an experienced immigration attorney. If you hire the attorney, they can analyze the facts of your case and spot any potential problems, prepare the paperwork, and monitor the progress toward approval.
Also see the Marriage-Based Visas and Green Cards section of Nolo's website for more information on your eligibility and the application process.