The blogosphere would have you believe that Facebook users are up in arms about the end of Facebook voting, Facebook private data policy changes, or almost anything Facebook does.
It's not true. The majority don't know about the issue. Of the minority that do know about the issue, the majority of these people don't care.
It occurs when people believe they have gained a consensus amongst the group. Many bloggers believe most people are anti-Facebook. You can use the Facebook vote as an example. Overwhelmingly, they claim, Facebook users voted against the changes. That's not true, only 0.067% did. The overwhelming majority didn't vote at all.
The danger of the false consensus bias is you encounter members in your community who not only passionately believe they're right, but firmly believe everyone agrees with them. Look at the % of members that are protesting, open it to a poll on the community platform, check how many people bother to vote at all.