However, now Facebook has indexed over 2 trillion posts, and its search function enables users to seek out a specific post from any public profile, regardless of whether the two are friends on the social network. Unfortunately, the new feature has led to concern that publications that many users would prefer to stay hidden will be revealed to everyone. Facebook explained that the search results are personalized and unique to each user and, as always, they can only see things that have been shared with them. Likewise, you are able to control who can see your posts on the service and it’s easy to change the audience of your past posts any time.
Since Facebook is 11 years old, some users have more than a decade of past posts indexed on the service. So, there is a chance they may not remember which posts were made with which privacy settings. As a result, this could lead to some uncomfortable posts resurfacing.
The decision to index older user posts is part of a Facebook’s attempt to compete with main rival Twitter on live events – this is something where Twitter’s broad search and chronological focus has given it the edge.
Recent changes, including Facebook’s “trending” bar, have let users search the service for current events, but until now, it was difficult to find and take part in the public conversation around what was going on out there.