There weren't many when it began, but today we have Google-plus, twitter, Reddit, Hacker-news and lots of others
That's not the real threat to Facebook's empire. Those are all tools used by people in their late 20s and 30s who came of age in a desktop-first world and Facebook is comfortable coexisting with them.
The thing that is a threat to Facebook long term is mobie apps like Snapchat, YikYak and other things we old farts haven't even heard of. They are used by (and represent) a new generation of truly mobile-first users for whom Facebook is something their parents ("old people") use. The biggest risk Facebook has with these users is not that it just unused, but uncool.
That's not the real threat to Facebook's empire. Those are all tools used by people in their late 20s and 30s who came of age in a desktop-first world and Facebook is comfortable coexisting with them.
The thing that is a threat to Facebook long term is mobie apps like Snapchat, YikYak and other things we old farts haven't even heard of. They are used by (and represent) a new generation of truly mobile-first users for whom Facebook is something their parents ("old people") use. The biggest risk Facebook has with these users is not that it just unused, but uncool.