Soon, you'll be able to throw data into /keybase/private/yourname,pal@twitter,
even if that Twitter user hasn't joined Keybase yet.
Your app will encrypt just for you and then awake and
rekey in the background when that Twitter user joins
and announces a key.
That said -- there are products that Shopify does (and would) kick a user for selling. Shopify isn't neutral, in fact, they're saying Breitbart is acceptable.