Facebook - Social App Virility

[ameyer]

Are some social app developers here?

There was some nice formula to calculate virility (n friends had to install an app after an app-user invited them....).
So as far as I know Facebook cracked down on forced virility and generally doesn't like viral apps any longer (especially those with senseless content that just spread through incentivized invites or shares).
They rater like apps that provides real use for the user and keeps them spending a lot of time on Facebook (e.g. the Netflix app?)

I'm wondering, are games like Farmville still viral?
If not, does virility in general play a role nowadays?

 

[ameyer]

P.S. if not for virility, what benefits does a developer have to develop a Facebook App compared to a standalone service?

 

[earl campbell]

I would love to see some data and benchmarks as well as best practices

Also -it's virality not virility - the latter is what u lose when you get to be my age