Can the cops get your online data? In short, yes. There are a variety of US federal and state laws which give law enforcement powers to obtain information that you provided to online services. But, there are steps you as a user and/or as a service provider can take to improve online privacy.
Law enforcement demanding access to your private online data goes back to the beginning of the internet. In fact, one of EFF’s first cases, Steve Jackson Games v. Secret Service, exemplified the now all-too-familiar story where unfounded claims about illegal behavior resulted in overbroad seizures of user messages. But it’s not the ’90s anymore, the internet has become an integral part of everyone’s life. Everyone now relies on organizations big and small to steward our data, from huge service providers like Google, Meta, or your ISP, to hobbyists hosting a blog or Mastodon server.
There is no “cloud,” just someone else's computer—and when the cops come knocking on their door, these hosts need to be willing to stand up for privacy, and know how to do so to the fullest extent under the law. These legal limits are also important for users to know, not only to mitigate risks in their security plan when choosing where to share data, but to understand whether these hosts are going to bat for them. Taking action together, service hosts and users can curb law enforcement getting more data than they’re allowed, protecting not just themselves but targeted populations, present and future.
This is distinct from law enforcement’s methods of collecting public data, such as the information now being collected on student visa applicants. Cops may use social media monitoring tools and sock puppet accounts to collect what you share publicly, or even within “private” communities. Police may also obtain the contents of communication in other ways that do not require court authorization, such as monitoring network traffic passively to catch metadata and possibly using advanced tools to partially reveal encrypted information. They can even outright buy information from online data brokers. Unfortunately there are few restrictions or oversight for these practices—something EFF is fighting to change.
Below however is a general breakdown of the legal processes used by US law enforcement for accessing private data, and what categories of private data these processes can disclose. Because this is a generalized summary, it is neither exhaustive nor should be considered legal advice. Please seek legal help if you have specific data privacy and security needs.