Have you noticed that even the websites which are not categorised under 'social networking' have socialising features? Take the popular online shopping master Amazon itself.
Leave aside the sites like company websites. They are most of the times expected to have company info and at the most email sending facility. Most of the other sites if you notice, will have some or the other social feature- chatting, connecting to people, following, rate, like, share, comments, reviews, collaboration. Entering feedback- review and rate is commonly available facility. I value rating so much that it becomes a judgement point for me whether to download/add an app or not from Google apps Marketplace or Chrome Extensions gallery. In my opinion there is even a need of 'social wiki' rather than just a 'wiki'. You might get multiple wiki pages for same search content. Would it not be nice to go and read the highly rated ones!
Do you think that any web app will flourish in present market even without any of the social networking flavors? I feel as though it has become a mandatory feature to have in any web app! Not that an enterprise app will not succeed without these features. But integration of social layer will add value to it!