The so-called “app gap” that separates Windows-based smartphones from their iOS and Android counterparts is very real. There are simply far more apps available in every category on the other two major platforms, and in many cases the equivalent apps are simply better. No matter how good Windows 10 Mobile becomes (it’s still in pretty rough shape at the moment), the platform will suffer until the app gap is closed.
Even so, there are actually only a handful of areas where it’s simply impossible to use a Windows phone. Social media is partly covered, for example, with a usable (but not terribly great) Microsoft-written Facebook app and plenty of decent Twitter apps. Instagram and Pinterest are covered as well, with third-party options of varying quality. Of the major social media platforms, in fact, only Snapchat is entirely missing in action (by Snapchat’s choice, of course).