Privacy is a feature, not a product. And I mean that in the literal sense, not the dismissive condescending way that people use it to describe startups they don't take seriously.

Privly is not disruptive because it doesn't remove people's desire to use Facebook. If it did manage to kill Facebook's business model, people would not be happy because it doesn't replace Facebook.

Of course this is a moot point because in general people don't care about privacy, so Privly can remain safely parasitic for the indefinite future. Eventually some major event or series of events may get people to take privacy more seriously, and in that case Privly would be well positioned for growth, but were such a sea change to occur Facebook would be the first casualty with or without Privly.