Is the FSF on Twitter?
We are there so that people new to the free software movement can learn about it, and because -- unlike with Facebook -- we have no ethical objection to merely having an account on Twitter.
However, we do find Twitter problematic, and there are some ethical pitfalls that come up the way most people use it. If you're currently a Twitter user, here are a few reasons to consider switching to GNU social, a free software (licensed under AGPLv3), decentralized microblogging service.
Twitter accounts have privacy issues, such as being vulnerable to broad subpoenas. Because Twitter accounts are centralized on one server, your account can be subpoenaed, and Twitter could be forced to hand over your information. This isn't a hypothetical: Twitter accounts have already been subpoenaed -- such as for Occupy. Decentralized services like GNU social, as well as the popular Mastodon and ActivityPub, mean that the developers don't necessarily own the servers hosting your posts or account information, making it harder for someone to execute a subpoena without your direct knowledge. Distributed servers are also less tempting targets for malicious crackers out to steal large amounts of personal information.
As a bonus, a federated system hosted on many servers is more durable than a centralized one. If we all continue to rely on Twitter, some day there will be a permanent fail whale. By contrast, when one part of a federated system (like email!) goes down, it does not take the entire network with it.
So, in support of software freedom and to protect your own information, switch from Twitter to a decentralized microblogging site. The GNU social project maintains a list of popular public GNU social instances for new users to try out. You can also set up an instance of GNU social for you and your friends by visiting the project's homepage. The FSF also has microblogging accounts at Diaspora and Mastodon. Another microblogging network is pump.io. You can sign up for any number of instances of pump.io by visiting the pump.io random instance selector. Or better yet, try pump.io out on a public instance and then get together with some friends to run your own.